pyro developer, but which? [Archive] - Large Format Photography Forum

Jay DeFehr

3-May-2010, 11:43

Sergio,

My favorite pyro developer is 510-Pyro. 510-Pyro is unique in several ways, most notably, it is a single, highly concentrated solution, much like Kodak HC110, that is simply diluted with water to make a working solution. 510-Pyro is suitable for all formats and development techniques, from rotary to stand development, and everything in between. I know of no other developer with greater development capacity; 1ml of 510-Pyro concentrate will develop an 8x10 sheet, or roll film. You can find more info here:

http://pyrostains.blogspot.com/

There are many good staining developers, some pyro, others catechol-based, that are capable of excellent results. In fact, I'd venture to say every published staining developer is capable of excellent results, but this should not suggest all staining developers are alike.

In my opinion, there are three significant pyro developers:

ABC Pyro

WD2D and variants

510-Pyro

ABC-Pyro (aka Kodak SD-1) has produced many historically significant, and beautiful negatives, but there are problems with its 3-part formulation and keeping properties that make it inconsistent in use.

WD2D is an excellent 2-part developer formulated for use with modern films.

510-Pyro is the only developer of its kind.

There are many catechol-based staining developers of varying complexity. My favorite is among the simplest. Hypercat contains the following ingredients:

Catechol
ascorbic acid
sodium carbonate
propylene glycol

Hypercat is an incredibly efficient, single agent, true acutance developer, and a working solution sufficient for development of 1 8x10 sheet or roll film contains .3g developing agent. The combined effects of a dilute single agent, tanning, and staining produce very sharp, fine grained negatives. Hypercat can be used as a single solution developer, or a 2-bath developer. You can find more information here:

http://hypercatacutancedeveloper.blogspot.com/

Among the most controversial issues regarding staining developers involves differences in stain colors, and printing on VC papers. Stained negatives scan very well, as evidenced by the beautiful work posted here by users of staining developers.

Good luck, and enjoy!

sergiob

4-May-2010, 08:25

Thanks a lot. I'll be posting my discoveries as soon as I receive it.

IanG

4-May-2010, 08:53

Segio, I regularly fly with my Pyrocat HD in my hold baggage, but I now only take Part A as it's easier to make up Part B anywhere.

To cut down on weight & bulk I now make up Part A at double the normal strength before flying then dilute it back to normal before using it as usual.

Ian

Ken Lee

4-May-2010, 09:36

Jay -

The 510-Pyro blog lists the formula as follows:

* ascorbic acid 5g
* pyrogallol 10g
* phenidone .25g
* Triethanolamine 100ml

I presume this makes 100ml of stock solution. How do we dilute the formula for use ? Are there any recommended starting points for time/temperature/film speed for various films ?

I would love to try the formula.

Is it called 510 because of the first two ingredients being 5 and 10 grams ?

Finally: You distinguish between Pryrogallol and Pyrocatechin/Pyrocatchetol, calling Pyrogallol "Pyro", and Pyrocatechin/Pyrocatechol "Catechol" or "Cat". I know these are two different compounds, but could you please explain why you refer to one as Pyro and the other, as... something else ?

Jay DeFehr

4-May-2010, 12:48

Hi Ken,

You're correct; the formula as given makes 100ml of concentrate, and I call it 510-Pyro for the ratio of pyro to ascorbic acid.

510-Pyro can be diluted over a very wide range, but "standard" dilutions could be considered to be 1:100, 1:300, and 1:500, for no better reason than the following: 1:100 gives development times within the low-normal range (5-7 minutes for most films), with standard intermittent, or rotary agitation, 1:300 requires 1ml of developer in 300ml of solution, which covers one 35mm film in a standard daylight tank, and 1:500 requires 1ml of concentrate in 500ml of solution, which covers one 120 film in a standard daylight tank. These dilute solutions are typically used with reduced agitation and extended development times. There is more specific information at the blog.

I make the distinction between pyrogallol developers and catechol developers consistent with historical usage. When pyro is mentioned in the literature, it always refers to pyrogallol, and not to catechol, and the descriptions and characterizations of pyro are not interchangeable with catechol. Catechol is chemically more similar to hydroquinone than it is to pyrogallol, and this can be confirmed by the fact that catechol can be substituted for hydroquinone weight-for-weight in most formulas without important changes in the resulting developers. The same is not true for pyrogallol and catechol. In my opinion, which is consistent with the historical literature, catechol developers should not be referred to as pyro developers, but staining/tanning developers, where appropriate (not all catechol developers are staining developers). I hope that clarifies my usage of the terms.

If you decide to try 510-Pyro, or any of my developers, please don't hesitate to contact me with any questions you might have.

sanking

5-May-2010, 06:20

I personally believe it is a waste of time equivalent to intellectual masturbation to attempt to limit the use of the term pyro staining developer to only pyrogallol based formulas. The word pyro itself has wide meanings both in photography and in general use and does not refer to any specific reducing characteristic of either pyrogallol or catechol (which was historically better known as either pyrocatechol and pyrocatechin).

As for which is the best pyro formula, I am reminded of something that was recently said to me in my travels in Galicia, in northwestern Spain. I was photographing there for a couple of weeks with a well-known landscape photographer from the area who has published a number of books, who actually uses a very old pyro-metol formula that pre-dates any of the modern formulas. He mentioned that he recently took someone to buy some “corn cakes” (tortas de maiz) from a person who is widely known for making the best cakes of this kind. The person asked, “Do you make the best corn cakes in Galicia?” to which the baker replied, “Eso tem que decir a torta, non eu” Translated, the cake has to speak to that, not me. So by analogy, I say, let your pictures talk.

Sandy King

Ken Lee

5-May-2010, 08:39

I confess, I'm confused.

Apparently, Catechin is derived from certain plants, and if you heat it (pyro) you can break off a molecule of Catechol (hence the name pyrocatechol).

In the image below, you can see a Catechol molecule, loosely bonded to a (larger) Catechin molecule.

According to Catechin (http://en.wikipedia.org/wiki/Catechin) in Wikipedia...

"Catechin... derives from catechu which is the juice or boiled extract of Mimosa catechu"

http://upload.wikimedia.org/wikipedia/commons/thumb/4/44/%28%2B%29-Catechin.png/200px-%28%2B%29-Catechin.png

According to Catechol (http://en.wikipedia.org/wiki/Catechol) in Wikipedia...

"Catechol, also known as pyrocatechol... Not to be confused with Catechin (http://en.wikipedia.org/wiki/Catechin), also sometimes called catechol."

http://upload.wikimedia.org/wikipedia/commons/thumb/e/ed/Brenzcatechin.svg/129px-Brenzcatechin.svg.png

sanking

5-May-2010, 09:35

I confess, I'm confused.

Apparently, Catechin is derived from certain plants, and if you heat it (pyro) you can break off a molecule of Catechol (hence the name pyrocatechol).
%29-Catechin.png/200px-%28%2B%29-Catechin.png[/IMG]

Hydroquinone (1,4,-Dihydroxybenzene), Catechol/Pyrocatechol (1,2-Dihydroxybenzene) and Pyrogallol (1,2,3-Trihydroxybenzene) are quite similar and while each can produce a stain in favorable circumstances (absence of preservative) neither is fully interchangeable with the other two. Hydroquinone can be substituted for pyrocatechol but does not give the same result (different color stain and different energy if substitution is by equal weight), and pyrocatechol can be substititued for pyrogallol in formulas that use carbonate as the accelerator (but equal weight substitution will not give identical results. Hydroquinoine and pyrocatechol can not be substitued for pyrogallol in formulas that use metaboate as the accelerator.

Sandy King

Ken Lee

5-May-2010, 12:03

sanking

5-May-2010, 12:57

Another question if I may, namely the difference between staining and tanning - and for that matter, dyeing.

With a stain or dye, we introduce a new compound deep into the matrix of the original material. With tanning, we coat the surface of the material, but do not penetrate very far below the surface.

By this analogy, a stain would be like a coloring stain we commonly apply to wood products, where tanning would be more like paint, applied to the surface.

If this is true, then as far as photography is concerned, what is the qualitative difference between developers which stain, and those which tan ?

Ken,

Stain adds printing contrast with graded silver papers and UV processes. It also can create a shoulder in the highlights with VC silver papers that can control very high tonal values. Stain also minimizes the appearance of grain. With enough preservative (sulfite, ascorbic acid, etc.) both pyrocatechol and pyrogallol based developers will lose the stain, but grain will be much more pronounced.

Tanning adds sharpness as it hardens the gelatin in situ and prevents infectious development outside of the desired image area. However, staining and tanning do not always go together as you can have staining without tanning, and vice-versa. Most modern pyro developers do both, however.

Sandy King

Jay DeFehr

5-May-2010, 13:59

Sandy,

Masturbation aside, I know of no instance in the literature I've read, and I don't mean to suggest I've read everything, in which the term pyro is used to refer to anything but pyrogallol. I see no reason to confuse this very old convention by the inclusion of other compounds. I use the term, staining developer to refer to all developers that produce a useful stain. Pyro belongs to this class of developers, when used in appropriate formulations, as do catechol, hydroquinone, coffee and tea developers. When one reads historical literature and comes upon the the term pyro, one can be confident the authors are referring to pyrogallol; why confuse the issue? I use catechol, as opposed to pyrocatechol, or pyrocatechin, or catechin, because that's how the chemical is listed by most suppliers, and I don't feel there's much danger of the term being confused for something else. Maybe I'm overly cautious in my use of language, but with so much confusion surrounding these developers, I feel justified in my efforts to be as clear as I can in my writing and in the terminology I use. For instance, consider the description of Pyrocat HD, from the Photographers Formulary website:

Pyrocat HD is a high acutance developer, formulated by Sandy King as an alternative to other pyrogallol based staining developers.

The use of the word other, implies Pyrocat HD is a pyrogallol-based developer, and since pyro is used in the product name, it's a logical assumption to make, if one is not intimately familiar with the compounds and formulations in question.

Others are free to use any terminology they prefer; I just meant to explain why I use the terminology I do, and not to suggest anyone is wrong for using alternative terms.

As for your corn cake analogy, you sum up as "Let your pictures talk", I feel that is a little aggressive in addition to being a gross oversimplification, unless of course, you believe developer choice is the one factor that determines the quality of an image. Personally, I feel developer choice borders on irrelevance, regarding image quality, for most LF photographers.

Ken,

Here's a link to a brief description of tanning and staining:

http://pyrostains.blogspot.com/2007/10/staining-and-tanning.html

In a nutshell; staining colors, and tanning hardens. The fact that tan, can be used to refer to a color, or a change of color, as in: tan trousers, or suntan, can be confusing, but the tan in tanning developers, is derived from the word tannin:

http://en.wikipedia.org/wiki/Tannin

I hope I've clarified rather than confused.

sanking

5-May-2010, 14:29

Jay

You are perfectly free to use any terminology you like. It is true that in the 19th century pyro meant pyrogallo. Indeed, pyrocatechol was not even invented until around 1880. However, in the contemporary period a number of pyrocatechol based staining developers, in addition to Pyrocat-HD, have been routinely referred to as pyro developers. These include Diaxactol, which preceded Pyrocat-HD, as well as Prescysol and Tanol. But more important than practice is the fact that pyrogallol based and pyrocatechol based developers do essentially the same thing in the way they stain and tan. In fact, the differences between them are more apt to be in the other reducer used in the formula, in the method of agitation, or in the choice of accelerator.

So my own opinion is that it is simply not consistent with current practice, or common sense, to limit the use of pyro to pyrogallol based developers, but then again you are free to use any terminology you like, and ultimately what you or I think is probably not going to make much difference as to what others choose to do. And that is why I think the discussion is essentially pointless.

As for my corn cake analogy being in your opinion a bit aggressive, it was not meant that way and I see no reason why you would take it that way since the comment was generally directed, not toward you. The original question was "which pyro developer"? and if the ability to produce image quality is irrelevant to that question it is not clear to me why we would be talking about developers in the first place.

Sandy

Jay DeFehr

5-May-2010, 18:46

Sandy,

You might be right about some catechol developers being referred to as pyro developers; I've just not seen these references in my reading, which has consisted mostly of 20th century literature, and as recent as I could find. In fact, in Barry Thornton's Edge of Darkness, Thornton distinguished between pyro developers and catechol developers, the former being developers based on pyrogallol. Jacobson and Jacobson in Developing similarly don't interchange the two, but refer only to pyrogallol-based developers as pyro developers, and so on with everything I've read . I'm not sure where catechol developers are referred to as pyro developers, but I'll take your word for it. Is it an important distinction to make? I think so. Pyrogallol developers have a separate history from catechol developers, and I find it more accurate to refer to pyrogallol developers as pyro developers, and catechol developers as catechol developers, and to all staining developers as staining developers. When one reads about the working methods of revered photographers, like Weston, or Adams, and their pyro developers, there is no need to wonder whether they used pyrogallol or catechol, because pyro is historically specific to pyrogallol developers. This is more clear to me, and a more common sense approach, than lumping all staining developers together as pyro developers. But, to each his own.

I'm sorry if I misinterpreted your corn cakes analogy as suggesting superior developers make superior images. I'm not sure what else, "let your pictures do the talking" could mean. In any case, it's not very useful in the context of a discussion about the relative merits of various staining developers. Weston made some pretty nice pictures with ABC Pyro, but that shouldn't suggest that developer was responsible, or that he couldn't have made his pictures as well, or better with another developer. "Let your pictures do the talking" is a meaningless statement in this context.

As for my statement, I wrote: ..developer choice borders on irrelevance, regarding image quality, for most LF photographers. , and I stand by that. But, the OP's question wasn't, "How important is choice of developer for LF photographers?", it was, "Which pyro developer is best?". The latter is a specific question about pyro developers, on which I feel qualified to comment. While I made a distinction between pyro and catechol developers in my post, I did include information about both kinds of staining developers, because I suspect many photographers, particularly those unfamiliar with them, think only of pyrogallol developers when they refer to pyro developers, and might not be aware there is more than one kind of staining developer, and they're not all pyrogallol-based.

In the end, whether one refers to all staining developers as pyro developers, or just pyrogallol developers, is of little importance, so long as it's understood who refers to which as what.

sanking

5-May-2010, 20:30

I'm sorry if I misinterpreted your corn cakes analogy as suggesting superior developers make superior images. I'm not sure what else, "let your pictures do the talking" could mean. In any case, it's not very useful in the context of a discussion about the relative merits of various staining developers. Weston made some pretty nice pictures with ABC Pyro, but that shouldn't suggest that developer was responsible, or that he couldn't have made his pictures as well, or better with another developer. "Let your pictures do the talking" is a meaningless statement in this context.

You rather misunderstood my meaning. My comment about the pictures talking was not meant to suggest there was a superior developer, but in fact to downplay the importance of any given formula, the very opposite of your interpretation.

Photographers who have a vision make superior photographs because they understand their tools, of which the developer is one of many. Weston made great photographs because of his great talent and because he knew how to control his tools, including ABC Pyro. I am certain that he could have learned to control other developers as well, but the fact is that he used ABC Pyro almost exclusively for much of his career because he understood how it worked and knew how to take advantage of its characteristics.

Developers, whether pyro or traditional, are not inherently either good, bad or in between. Same is true of films. They have characteristics which one must learn how to control. When one learns this control, the pictures do the talking. One may compare the various characteristics of different developers and films but that will tell you little or nothing about what kind of images a given photographer will produce when using any given combination.

Sandy King

Kirk Gittings

5-May-2010, 20:39

FWIW

Pyrocatechol is the name recommended by the International Union of Pure and Applied Chemistry (IUPAC) in its 1993 Recommendations for the Nomenclature of Organic Chemistry.[1]

quote from:http://www.search.com/reference/Pyrocatechol

Jay DeFehr

5-May-2010, 22:01

Sandy,

I'm afraid your analogy is not at all clear to me. In fact, I can't make heads or tails of most of what you've written in this thread, but that's neither here, nor there, as none of it, so far as I can tell, addresses the OP's question. I think we agree that developer choice is one factor of many that combine to determine image quality, but I can't be sure, even of this. And even if we do agree, this is not relevant to the OP's question about pyro developers, and probably best discussed elsewhere.

Kirk,

Thanks for the official word on the nomenclature of pyrocatechol. Still, if one is looking for the chemical at Artcraft Chemicals, or Photographers Formulary, etc., it will be found under C for Catechol, and not under P, for Pyrocatechol, for whatever reason.

sanking

6-May-2010, 05:26

Sandy,

I'm afraid your analogy is not at all clear to me. \

Since what I previously said was not clear to you, let me wrap up.

1. The OP was interested in a pyro type developer that would fly, presumbably with him. I don't recommend this as any unusual looking chemical has a good chance of being pulled from your luggage or carry-on baggage in the current climate of terrorist threads. In the last five years or so I have lost quite a number of expensive chemicals this way so my recommendation at this point would be to have the developer shipped from a well-known supplier.

2. All of the major pyro tanning developers, whether pyrogallol based or pyrocatechol based, have certain pros and cons and require some experience to use. While some of the formulas can be classified as general purpose developers I would never recommend one over the other without understanding the specific type of photography the person had in mind because making good images is much more about understanding how to use a developer than the technical qualities of the developer.

3. Pyro staining and tanning developers, as I use the term, include both Pyrogallol based formulas and Pyrocatechol based formulas. Most people, in my experience, tend to lump these together in one group known as pyro staining and tanning developers. This seem reasonable to me because they all basically do the same general thing, i.e. they add a color stain to the negative, and they harden the gelatin. I use the duck analogy here. If it walks like a duck, looks like a duck, quacks like a duck, I am ok with calling it a duck.

People who don't agree with my opinion are obviously free to use whatever nomenclature they choose. But this is where I stand, and by and large I believe my position is consistent with current practice, starting with Chapter 8 (Tanning Developers) of The Film Developing Cookbook (Anchell and Troop, 1998) where both pyrogallol and pyrocatechin are discussed together as equally effective staining and tanning developers.

Sandy King

Jay DeFehr

6-May-2010, 09:54

Sandy,

Thank you for the clarification, and please find mine below:

1. I fly every three weeks, year round, and have never had a problem carrying a small bottle of 510-Pyro. Even if I did lose it, it would be more of an inconvenience than an expense, on a par with losing cheap shampoo.

2. I wouldn't hesitate to recommend 510-Pyro to anyone interested in trying a staining developer; it's the easiest to use, works with all films and formats, and all development processes. I sincerely believe 510-Pyro is the best staining developer one can use, and particularly for a beginner. Others are free to disagree, of course, and I think the OP is looking for opinions on the pros and cons of various staining developers. I mentioned 510-Pyro because I think it's the best all around staining developer, for many reasons, and I mentioned Hypercat because I think it's the sharpest staining developer, and surely the simplest in formulation, and most economical to use. In short, unless maximum acutance is desired, I recommend 510-Pyro, and if maximum acutance is desired, I recommend Hypercat. These recommendations stand without regard to the user's experience or specific intentions. I don't mean to say there are not many other staining developers capable of excellent results;there are, but in my opinion, some are better than others, and my recommendations reflect my opinions.

3. I think the term staining and tanning developer is more clear than pyro staining and tanning developer, but this is an insignificant issue. Ken asked why I use the terminology I do, and I did my best to explain my reasons. Others are free to use whatever terminology they choose. I don't think anyone is going to be confused when I refer to pyrogallol-based developers as pyro developers, or catechol-based developers as catechol developers, or staining developers, in general, as staining developers.

Ken Lee

6-May-2010, 10:34

Thanks, fellers, for taking the time to explain these things in such detail.

Since this thread has already had close to 1000 views, we can trust that others share an interest, but may have been reluctant to enquire.

Jay DeFehr

6-May-2010, 11:06

Ken,

I'm always happy to contribute where I think I can. I would like to reiterate that I think developer choice is very low on the complete image quality totem pole, as evidenced by the very fine work posted here, using a wide variety of developers and processes.

sanking

6-May-2010, 13:01

I was just glancing through Steve Anchell's The Darkroom Cookbook, Third Edition. He has a chapter entitled Pyrogallol and Pyrocatechin, and within that chapter a section called Tanning Developers. In this section he lumps pyro and catechol developers together with the term "pyro/cat" developers, which he uses numerous times. However, in the same section he sometimes uses "pyro" without "cat" in situations where it is obvious that he is talking about both pyrogallol and pyrocatechin formulas.

This is a good example of what I consider contemporary practice in the use of terminology. I did not invent this stuff, just reporting what appears to me to be the general practice.

Obviously there are situations where one might want to be more specific as to the nature of the reducers in a staining/tanning developer as the characteristics of pyrogallol and pyrocatechol, while very similar, are not exactly the same, and a case could be made here and there that for a given objective one of the other might serve better.

Sandy King

Ramiro Elena

6-May-2010, 15:53

sanking

6-May-2010, 16:13

Do you guys know the Argenti Weston Pyro developer? The reason I ask is it's the only developer of this kind I've seen available in Spain (I suppose others could be found) and I'd really like to give it a go.

BTW I am curious now as to who the known landscape photographer is :D

I am not familiar with the Argenti Weston Pyro developer but if it has Weston in the name I suspect that it is similar to ABC Pyro.

The photographer I mentioned is Jose Vazquez Caruncho, from La Coruña. He has several published books and has done a lot of work for the Xunta de Galicia and the CGAI. You can see a fair amount about him by doing a google search. He does beautiful portrait work rather in the style of Paul Strand.

Sandy King

Brian Stein

6-May-2010, 20:24

1. I fly every three weeks, year round, and have never had a problem carrying a small bottle of 510-Pyro. Even if I did lose it, it would be more of an inconvenience than an expense, on a par with losing cheap shampoo.

I assume you are carrying the made up solution in a 100 ml bottle, not labeled with (from customs eyes) some obscure chemical name. I would expect this to be fine.

Now, put a brown powder in a bottle with a chemical label on it that also says poisonous and have your luggage searched..............

Jay DeFehr

6-May-2010, 21:21

Brian,

I carry my developer in a small, unmarked bottle. I've never had a problem. I've never even considered trying to carry powders in my luggage; that seems like asking for trouble.

Andre Noble

7-May-2010, 07:32

I went back to Wimberly WD2D+ pyro developer after giving Pyrocat HD a go.

I recently printed a WD2D+ developed negative (I believe it was Kodak Tri X) of a portrait shot between shade and direct sun. It had a huge subject brightness range. Once I set the correct exposure in the enlarger and viewed the first test prints, the idea never occured to me that I needed to do any buring to get proper details in the highlights. This does not occur with traditional developers.

Also, although not touted as a developer for rotatry processing, I have gotten beautifully clean wd2d+ negs by in my jobo cpp2 but using slowest rotation speed and replacing the developer mid way through development time with fresh wd2d+ developer.

I have to admit that WD2D+ negatives with their yellowish brown color look kind of 'weak'. But the are a dream to print.

onnect17

15-Dec-2010, 02:21

Remember, "The milk-man did not get caught for adding water to the milk; he just told someone".

Brian,

I carry my developer in a small, unmarked bottle. I've never had a problem. I've never even considered trying to carry powders in my luggage; that seems like asking for trouble.

Bruce Barlow

15-Dec-2010, 03:48

Ok, experts. I hate using gloves. Pyro is toxic, and everyone says to use gloves.

Did Weston use gloves? His volume of negatives will exceed mine (in quantity as well as, most certainly, quality).

What's likely to happen if I don't? Will I shrink, for instance? I'm 6'6". I'd probably like that. Won't bump my head on the doors of my old NE farmhouse.

Ditto amidol, for the informed. What would happen?

Sorry to be slightly off-topic, but I think still relevant, sort of.

Mark Sampson

15-Dec-2010, 07:35

Bruce, if nothing else, contact dermatitis is a very nasty thing. I was lucky, my case cleared up quickly. But everyone is different; and once you're sensitized, there it is. Many people are permanently affected and have to give up the darkroom; I don't think you'd like that. In Weston's day, little was known about the toxicity of common photo chemicals, now we do. Remember that EW contracted, and died of, Parkinson's disease. AFAIK no one has connected that to his darkroom habits but how big a risk do you want to take?
Pyrogallol hasn't been extensively studied because so few modern photographers use it. Metol, on the other hand, is a well-known source for contact dermatitis. (I believe that it was Selectol-Soft that made me allergic to metol.)So since 1985 I've worn gloves to tray-develop sheet film and to print. Not a big deal.
Safe practices are generally worth the effort.

Vlad Soare

15-Dec-2010, 08:06

Did Weston use gloves?
I believe he didn't, but Parkinson's disease is a really nasty thing. Was it related to darkroom chemicals? Maybe, maybe not. We'll never know. But why take chances?
Amidol, if nothing else, stains your skin and nails pretty badly.
I also wouldn't be too surprised if some of the chemicals, especially those derived from phenol, had carcinogenic effects on long term exposures. They may not have been proven as such yet, but again - why take chances?
Contact dermatitis is real, and quite nasty at that.

Bruce Barlow

15-Dec-2010, 08:08

Thanks. "get over it," and "get used to them" seem to be the operative phrases. So be it.

David Aimone

15-Dec-2010, 08:11

I'm about to mix up my first batch of Pyrocat-MC in glycol. Considering how important health is, I'm going to wear nitrile gloves and develop in the jobo tank. It's not worth the risk. My skin gets a bit dry and irritated if I don't use gloves with D-76, Dektol, etc.

It was quite a few years ago, but I remember reading a table top book in NYC about artists through the centuries. It documented their work processes, their illnesses and causes of death, and proposed links between the two. It was very interesting! Many were probably at times "mad as a hatter" too!

Of course there are a few individuals around here who could probably use that excuse...
;)

Pawlowski6132

15-Dec-2010, 08:45

Thanks. "get over it," and "get used to them" seem to be the operative phrases. So be it.

Bruce, I was the same way. Horrible contact dermitis resulting from Metol exposure changed my tune fast. I use Pyro and Amidol.

I get the smallest, tightest pair of gloves I can find and, I can pick up a dime or, perhaps more appropriate, pull an 8x10 negative out of the holder. Just be careful and monitor for holes and tears.

I buy 'em boxes from the drug store and leave 'em on my counter. It really doesn't take much to get used to 'em.

bob carnie

15-Dec-2010, 08:50

One of the best darkroom printers in Toronto had to quit the darkroom because of this.
I am no expert but for years I worked with my hands with no protection, I do have some funny marks and scars on my hand. That was enough to scare me.
Also at 5ft 6 I cannot afford to shrink much more so its gloves for me.
and everyone who works in my darkroom.

Bruce, if nothing else, contact dermatitis is a very nasty thing. I was lucky, my case cleared up quickly. But everyone is different; and once you're sensitized, there it is. Many people are permanently affected and have to give up the darkroom; I don't think you'd like that. In Weston's day, little was known about the toxicity of common photo chemicals, now we do. Remember that EW contracted, and died of, Parkinson's disease. AFAIK no one has connected that to his darkroom habits but how big a risk do you want to take?
Pyrogallol hasn't been extensively studied because so few modern photographers use it. Metol, on the other hand, is a well-known source for contact dermatitis. (I believe that it was Selectol-Soft that made me allergic to metol.)So since 1985 I've worn gloves to tray-develop sheet film and to print. Not a big deal.
Safe practices are generally worth the effort.

tbeaman

15-Dec-2010, 10:23

imagedowser

15-Dec-2010, 10:23

The Darkroom Cookbook, 3rd edition, Anchell... index:" Pyro. see pyrogallol (pyro) " The Negative, Adams... Index: "Pyro (pyrogallic acid, pyrogallol)" Both index listings are followed by Pyrocatechin as a separate listing. I've been processing film since 1950 and my understanding is pyro is pyrogallic acid, pyrocatechin is not... I don't own a photographic dictionary but I bet it's in there with pyrogallic acid as the primary meaning.... First thing you learn in stress reduction is not to HAVE to be right... hate to loose anyone over a pissing contest on developers.

Vlad Soare

15-Dec-2010, 10:31

Pyrogallol is 1,2,3 tri-hydroxy-benzene.
Pyrocatechin, or catehol, is 1,2 di-hydroxy-benzene.
They are not the same thing.
"Pyrogallic acid" is an improper name for pyrogallol (which is actually not an acid).
The short name "pyro" usually refers to pyrogallol, though the syntagm "pyro developer" is sometimes used for designating all staining developers in general.

You often hear the advice to use gloves, but rarely is it specified which kind. Are the thin nitrile or latex ones satisfactory, or is it better to step up to some kind of thicker rubber? Dishwashing gloves?
Right now I'm using unpowdered nitrile gloves. Before discovering these, I used to use regular latex surgeon's gloves from drug stores, but I didn't like them because they were powdered, and everything I touched remained white. Dish-washing gloves are fine from a safety point of view, but I think they're too clumsy for the kind of work required in the darkroom.

tbeaman

15-Dec-2010, 10:35

Pyro is just a shortform colloquialism, and both of those chemicals start with "pyro". I can see how it might be confusing or not matter for those not of the cloth.

Can't Pyro be an umbrella term for both? They're not all that incredibly different anyway, and where they are, it doesn't seem any more substantial than the differences between developers within other categories.

Right now I'm using unpowdered nitrile gloves. Before discovering these, I used to use regular latex surgeon's gloves from drug stores, but I didn't like them because they were powdered, and everything I touched remained white. Dish-washing gloves are fine from a safety point of view, but I think they're too clumsy for the kind of work required in the darkroom.

I agree, that's why I wondered about the nitrile/latex. Thanks.

matthew klos

15-Dec-2010, 10:37

I posted on here awhile ago talking about my problems with pyro i have since worked out the kinks. I shoot FP4 and i develop in PMK, and it works very nicely for me. For the project i am working on i have been shooting with a hasselblad and with direct flash, and i find the pmk does wonders for skin tones. It works for me.

Vlad Soare

15-Dec-2010, 10:46

Can't Pyro be an umbrella term for both? They're not all that incredibly different anyway, and where they are, it doesn't seem any more substantial than the differences between developers within other categories.
Interestingly, catehol is closer to hydroquinone than to pyrogallol. Hydroquinone is 1,4 di-hydroxy-benzene. They're almost the same, it's just the position of a hydroxyl group that differs. :)
Catehol and pyrogallol behave quite differently. The only thing they have in common is that they're both staining developing agents. But then, so can be hydroquinone.

I think it's best to be aware of the differences and to always call them by their proper names. This way we'll avoid any confusion, particularly among people who are new to staining developers and/or have no background in chemistry.

sanking

15-Dec-2010, 11:32

Catehol and pyrogallol behave quite differently. The only thing they have in common is that they're both staining developing agents. But then, so can be hydroquinone.

Actually both pyrocatechol and pyrogallol are staining *and* tanning developers. The tanning quality is in my mind more important than staining since it is tanning that makes these developers sharper than traditional developers.

I am not sure what you mean by when you say that catechol and pyrogallol behave quite differently. There are some differences to be sure but in my experience the two reducers actually behave very much alike. They both stain in the absence of sulfite or ascorbic, they both tan gelatin, and they both produce oxidation by products that can create B+F stain if the formula is not well balanced.

Sandy

sanking

15-Dec-2010, 11:36

Can't Pyro be an umbrella term for both? They're not all that incredibly different anyway, and where they are, it doesn't seem any more substantial than the differences between developers within other categories.

If a developer stains and tans I place it in a category called Pyro staining and tanning developers, regardless of whether the reducer is pyrocatechol, pyrogallol, or hydroquinone (which can also stain and tan in some conditions).

Sandy King

Vlad Soare

15-Dec-2010, 12:05

Actually both pyrocatechol and pyrogallol are staining *and* tanning developers.
Indeed, they're also tanning. I keep forgetting that. My mistake. But this has nothing to do with the fact that pyrogallol and catehol are two different chemical compounds, with different physical and chemical properties, which should be called by their proper names to avoid any confusion.

I am not sure what you mean by when you say that catechol and pyrogallol behave quite differently. There are some differences to be sure but in my experience the two reducers actually behave very much alike.
I don't have your experience with formulating developers, so I'm not going to contradict you here. My impression was that if one were to roughly describe them, one could say that pyrogallol tends to give coarse grain, lower film speed, a pronounced toe, and yellowish-green stain, while catehol, especially in conjunction with phenidone, tends to give fine grain, good film speed, a shorter toe, and brown/reddish stain. But of course this depends a lot on the overall formula, and if you're saying they are really so much alike, then I have no reason not to believe you. Do you think you could make Pyrocat work the same by replacing catehol with pyrogallol, without making major changes to the rest of the formula? I'm not trying to provoke you, I'm genuinely interested.

Drew Wiley

15-Dec-2010, 12:06

Gloves: For chemcial mixing and general dkrm activities I prefer slightly loose-fitting
thicker nitrile gloves, which can be taken on and off easily and aren't fragile. For actual
film hanling and tray development, I use thin disposable non-powdered (but textured) nitrile gloves. Nitrile is now priced barely higher than latex, and is superior is many ways. PYRO: I've tried quite a few different formulas and even concocted a couple of
my own, of both pyrocat and pyrogallol. The pros and cons are subtle but worth knowing. The color of image stain can be important with respect to a particular light
source and type of paper (VC vs blue-sensitive). Performance on long-scale contact
media vs ordinary silver projection papers also is a significant factor in the opinion about which "pyro" is "best" for what. But most of the popular options are in my own
"non-humble" opinion going to give much more easily printable negative than conventional "non-pyro" developers. Well worth learning the ropes. I'd probably start
with something with a lot of background info readily accessible, like Gordon Hutchings
PMK formula or one of Sandy's popular pyrocat ones.

sanking

15-Dec-2010, 12:31

Do you think you could make Pyrocat work the same by replacing catehol with pyrogallol, without making major changes to the rest of the formula? I'm not trying to provoke you, I'm genuinely interested.

Pyrogallol and pyrocatechol will give fairly similar results by replacing one with the other, if the alkaline accelerator is high enough for pyrocatechol. Pyrocatechol needs a threshold pH of about 10.9, pyrogallol only about 9.6. The two can not be exchanged in the PMK formula, which uses metaborate as the accelerator, but they could be exchanged in the WD2D formula, which uses a higher pH carbonate accelerator.

The other major difference between Pyrocatechol and Pyrogallol is that the former is much more sensitive to sulfite and ascorbic than the latter. A pyrocatechol staining and tanning formula must be well balanced without too much sulfite or ascorbic or you will kill the stain. You can use a lot more sulfite and/or ascorbic in a pyrogallol formula without killing the stain, though if you add enough at some point there will be no stain with a pyrogallol formula either.

Sandy

Barry Kirsten

15-Dec-2010, 13:45

An interesting thread - thanks to all who have contributed.

When I was previously active in b&w photography I used D7 then changed to PMK when it came out. Recently returning to photography I started where I left off, with PMK and the same good results I was previously used to.

Obviously things have moved on in the last few years, with new formulations like 510 and Hypercat, about which there has been quite a bit said so far. There have only been a couple of passing mentions made of PMK, and I'm getting the impression that it's no longer as well regarded as it used to be. Am I right in believing that the concensus is in favour of 510-Pyro these days?

Barry.

Jay DeFehr

15-Dec-2010, 14:57

sanking

15-Dec-2010, 16:02

Hi Barry,

While I believe 510-Pyro is a better developer than PMK, I don't think there's any kind of consensus to that effect, and I suspect PMK is still more popular than 510-Pyro is. I also suspect you're confusing Hypercat with Pyrocat, the latter of which is very popular and the former of which almost no one uses.

Sandy,

While I agree with your post above, in principle, I disagree with your numbers regarding the pH threshold of Pyro developers. 510-Pyro working solutions range from pH 8 +/- @ 1:500 to pH 8.5 +/- @ 1:100; very similar to D-76, and Xtol, which I believe contributes to the very fine grain 510-Pyro produces compared to other staining developers.

Jay,

I can not be absolutely sure about the pH because pH meters, except the most expensive ones, may give unreliable readings. However, I have over the years measured many TEA solutions in the 1:50 - 1:200 range, with several different pH meters, and in every instance the pH was in the 9.2 - 9.8 range. Perhaps the threshold development for pyrogallol + phenidone is lower than 9.2, but that is the lowest figure I have gotten with TEA solutions in the range noted above.

My own take on why 510-Pyro gives such fine grain is that there is some kind of solvent agent in the TEA. And that makes sense to me since in spite of some fine qualities 510-Pyro is not, IMO, a high acutance developer. The same is true of my Pyro Uno formula, i.e. the grain is very fine but I don't find it nearly as sharp as Pyrocat-HD or -MC.

Sandy

Jay DeFehr

15-Dec-2010, 18:45

Hi Sandy,

I use pH paper test strips, and I'm not very confident in their accuracy, so I retract my objections to your numbers. You're probably right. 100ml of 1:100 dilution of 510-Pyro contains something less than 0.85g of TEA, and 0.15g of acids in the forms of pyrogallic and ascorbic acids plus a tiny amount of phenidone, which is also acid. Obviously, some of the TEA is used up in converting the acids, or buffering, leaving less than 0.85g as a base. The resulting solution is apparently well buffered, whatever its pH, and can be diluted 1:500, or more.

I think the purported solvent effect of TEA is a myth based on the assumption that TEA contains some DEA, which 85% TEA does, but 99% TEA does not. Given that the solvent action of DEA is much less than that of sodium sulfite, even if 510-Pyro was made up entirely of DEA instead of TEA, there would be nowhere near enough of it in a working solution to produce a solvent effect. I don't recommend the use of anything but 99% TEA, and never LFG-type (Low Freeze Grade) which contains 15% water. There is nothing in 510-Pyro to act as a silver solvent, and it produces very sharp negatives, at least as sharp as any of the Pyrocats, in my opinion, though I don't consider either to be high acutance developers, but rather very good all-purpose developers. If 510-Pyro developed negatives appear less sharp than negatives developed in the Pyrocats, I suspect it is due to the finer grain of the 510-Pyro developed negatives.

Theoretically, for the highest possible acutance I prefer single agent developers like Hypercat or my glycin developers, all of which are sharper than 510-Pyro, and grainier. In practice, sharpness is not my first priority, or even my second, and almost any developer is sharp enough for me, and many are too sharp, or too coarse in gradation. Lately I've used almost exclusively my superfine grain developer, and I'm very happy with it.

onnect17

15-Dec-2010, 19:54

From the Glossary of the oldest text I own "The Book f Photography" 1907 :D

sanking

16-Dec-2010, 08:38

Jay,

I mention the possibility of solvent action of TEA since it was advanced by a former photo engineer at Kodak some years ago, in another discussion on another forum. I can not confirm or deny the the theory and was only advancing the possibility as an explanation for fine grain given the fact that my pH readings of TEA solutions in the 1:50 to 1:200 range have always been quite similar to those I get with sodium metaborate as in the B solution of PMK.

Sandy

onnect17

16-Dec-2010, 11:08

Drew Wiley

16-Dec-2010, 11:11

Barry - I still prefer PMK as the most versatile of the pyro developers for enlargement.
Some of the subsequent tweaks fall into discrete categories: 1) experimenting just for
the fun of it; 2) finding something which will allow the same neg to work reasonably per
highlight gradation for both enlargement as well as for longer-scale contact printing; 3) attempting to get better shadow value out of films with a little too much toe, like HP5+; 4) ongoing wars about what is the best color of image stain for whatever. I have tried a lot of tweaks and formed certain practical opinions. Somebody like Sandy would be a far better person to ask about for anything resembling alternate or contact processes. So much of the whole pyro topic is about subjective nuances with particular films, and not a totally cut-and-dried science. One person likes crisp grain,
another likes "watercolor" grain; one person uses a lightbulb hung from the ceiling,
another uses a blue-green cold light in an enlarger, etc, etc. Most of the popular formulas give very good results with a variety of films; but as one fine-tunes his particular taste with specific images, things tend to get more nitpicky.

Jay DeFehr

16-Dec-2010, 11:23

Sandy,

I know Ron mentioned the possibility of a solvent effect he associated with DEA, which is present in some grades of TEA, but that was something of a red herring, for the reasons I noted above. You know how these kinds of things get perpetuated on the net, and I wanted to clarify the issue.

I'm not sure why 510-Pyro produces finer grain than other staining developers. I suspect pH plays a role, especially when compared to catechol based developers, but I can't prove it. I think it's probably a combination of factors including surface development, tanning and staining, but I'm confident a solvent effect is not among them.

Jay DeFehr

16-Dec-2010, 12:00

I started to read some books about film developing and looking in the formulas. I'm trying to position the 510-pyro but the closest I can see is a mix of PC-TEA with pyro added.
Could anybody explain the differences between those developers?
Maybe I'm missing something.

There are hundreds (at least) of developers constituted from the same few chemical components, that vary dramatically in their working properties. The important differences lie in the ratios of the components, and their balance. The use of TEA as a solvent and a base, permits some deviations from standard developer formulation, and 510-Pyro takes advantage of some of them. Developers typically use a sulfite, or combination of sulfites as a preservative, but sulfites don't dissolve in TEA, so ascorbic acid is used a s a substitute. Ascorbic acid is also a reducing agent, but this role is secondary in 510-Pyro. 510-Pyro is not very similar to any other developer in formulation, or in working properties. PC-TEA is an excellent developer, in my opinion, but it has little in common with 510-Pyro, regarding its working properties.

onnect17

16-Dec-2010, 16:15

Jay, thanks for the quick response. Mr Anchell listed ascorbic acid as a developer in the book "film developing cookbook" and 5g is still a good amount. Seems to me the acid is sharing the developing action with the pyro.

Jay DeFehr

16-Dec-2010, 17:34

Ascorbic acid is certainly a developer, but it's contribution as a developer in 510-Pyro is not very significant. If the ascorbic acid is omitted from 510-Pyro, degree of development is not much affected, but general stain increases and the working solution oxidizes much more rapidly. If either pyro or phenidone is omitted, degree of development is greatly affected. PC-TEA uses about 2g ascorbic acid and 18g of TEA/ liter of working solution, along with some phenidone, and develops FP4+ in about 8:30. 510-Pyro uses about .5g of ascorbic acid and 8.5g of TEA/ liter, and develops FP4+ in about 6:00. The amount of development produced by .5g of ascorbic acid in 10ml of TEA in 6:00 of development is practically nil, even with the phenidone. Ascorbic acid is a developer and does contribute to development in 510-Pyro, but that contribution is practically insignificant, and secondary to its role as a preservative.

sanking

16-Dec-2010, 20:21

I have a formula that is similar to 510-Pyro, and influenced by its design, called Pyro Uno. I introduced it a couple of years ago but have not had time to devote much time to development. By that I mean systematic testing to determine time time and development for most of the common films. However, at the 1:100 dilution development times are very close to what you would need for Pyrocat-HD or Pyrocat-MC.

Pyro Uno contains pyrogallol + metol + ascorbic acid and differs from 510 Pyro in three ways, 1) metol replaces phenidone, and 2) the amount of pyrogallol in the formula has been reduced by 5%, and 3) the amount of ascorbic acid has been reduced by about 25%.

Pyro Uno
TEA (at 150F) 750 ml
Pyrogallol 95 g
Ascorbic Acid 38 g
Metol 30 g

TEA to make 1000 ml

Mix chemicals in order listed. Will dissolve easily with a hot plate stirrer at about 150F.

Working Solution: 1:50 to 1:200, 1:100 normal.
Starting point development time: 10-12 minutes with 1:100 dilution
Gives very low B+F, low general stain, and high image stain.

My primary objective in creating this formula was to, 1) test metol in place of phenidone in a pyrogallol + ascorbic developer mixed in TEA, and 2) have something to recommend to folks who are severely challenged in mixing two part developers like Pyrocat-HD. Over the years I must have answered over a thousand questions on the forums and in private email from individuals who screwed up the mixing of the Pyrocat formula and then instead of blaming themselves blamed the formula for their problems. The beauty of one solution formulas like 510 Pyro and Pyro Uno is that it makes it pretty easy to determine if the problem was the developer, or the incompetency of the person.

Sandy King

onnect17

16-Dec-2010, 21:06

Jay and Sandy,
Thanks for your posts. My order of pyrocat from Photoformulary is taking 10 days to reach Boston. A lot of reasons, 2 weekends, UPS routing, etc.
The good news is that the wait (and mostly your comments) sent me to the bookshelf and I’m having a blast reading about film developing. I was tempted to place another order for the ingredients of 510-Pyro but it seems too much. Now, if you’re working on Pyro Uno and they share some components then the new order is justified.
Regarding Pyrocat, I had the stock solutions in water for about 3 years and not major issues besides higher general stain. It just work.
Again, thanks to both for your input.

John Schneider

16-Dec-2010, 21:51

You often hear the advice to use gloves, but rarely is it specified which kind. Are the thin nitrile or latex ones satisfactory, or is it better to step up to some kind of thicker rubber? Dishwashing gloves? What about my wool winter mittens? There's all kinds of them out there.

Latex gloves are really designed for biologicals in health care (eukaryotic cells, bacteria, parasites, pathogenic agents, etc.) and aqueous solutions like the cell culture buffers you handle doing biochemistry. Their chemical resistance is minimal. Nitrile gloves have much better chemical resistance, but many ketones and aromatic hydrocarbons (like most developers) go right though them (I used MEK/xylene mixtures in my research, and for that you need either the thick rubber "acid" gloves or the thin multi-layer "barrier" gloves). Since these chemicals are in dilute aqueous solutions for developing, I *assume* that nitrile would be fine. I have tried to find glove permeability data for solutions like developers, but have had no luck.

Vlad Soare

17-Dec-2010, 00:29

Is there a developer that uses catehol as the only developing agent?

John, you raise an interesting point. We assume gloves to be safe, but I can't remember seeing any specific info on their permeability. However, circumstantial evidence seems to be against this. My hands are perfectly clean and dry even after hours of immersing them in amidol, or half an hour of tray development in ABC Pyro. The slightest trace of amidol leaves a permanent and obvious stain on any porous surface, including skin, nails, or even the nitrile gloves themselves. And yet my hands are perfectly clean, and even the inside of the gloves is perfectly clean when I get them off my hands. ABC Pyro leaves red stains on everything it comes in contact with (though these are easy to clean, unlike amidol stains). There's no trace of red on my hands or on the inside of the gloves. Amidol and pyrogallol are both aromatic hydrocarbons. I agree this doesn't actually prove anything; it's rather circumstantial evidence.
Maybe gloves can be penetrated by liquid hydrocarbons (like, say, benzene), but not by aqueous solutions of solid hydrocarbons? I don't know, I'm just thinking aloud.

Gary L. Quay

17-Dec-2010, 02:59

For the off-topic glove discussion: I just found some gloves at a CarQuest store in Portland called "Raven." They're black and non-powdered. Significantly, they are tough, and can be taken off and put on many times, even with damp or wet hands. None of the other gloves I've tried can do this. During my last prnting session, I used one pair, removing them to handle the film and paper (contact printing) and putting them back on before the using the developer. I didn't have to break out another set until I went to the toning bath because I didn't want residual fixer on my hands in the toner. I will use the same pairs next printing session. No rips, no fuss, no holes.

No, I don't own stock in the company. I just want to pass along this find. They are about 50 percent more expensive than the other gloves I've tried, but I use far fewer of them, which makes them cheaper to use.

--Gary

Jay DeFehr

17-Dec-2010, 09:14

Vlad,

There's at least one-

Hypercat

A
Propylene Glycol 75ml
ascorbic acid 1g
catechol 10g
PG to 100ml

B
Sodium carbonate 20%

Dilute 1:5:100

Develop Acros 8:00/ 70F, agitate 10 sec/minute.

Hypercat is a true acutance developer, and not well suited to rotary development. Agitation frequency can be decreased to 10 sec/ 3:00 for increased edge effects.

The above developer shares its name with another catechol developer I formulated years ago. That developer used catechol, ascorbic acid, phenidone, and benzotriazole in glycol, with a sodium hydroxide B solution. The original Hypercat worked great, but it was too complicated and did nothing that 510-Pyro didn't do, so I set my mind to formulating a developer that optimized the special characteristics of catechol. I learned that catechol didn't need the help of a secondary developer, and in fact, a secondary developer diminished the qualities of the primary one as an acutance developer. The elimination of the secondary developer confers several benefits. Since there is no regeneration of the primary developer, all the good things associated with preferential exhaustion are maximized, ie local contrast, adjacency effects, and compensation of the type that retards development in the highlights while continuing in the shadows for increased film speed. To be clear, I don't mean film speed increased over box speed, I mean increased over that obtained with rotary development or other continuous agitation. When used with standard intermittent agitation, Hypercat produces box speed, or perhaps a little better with most films I've tested. Further, by eliminating the secondary developer, fog and general stain are much decreased. Catechol itself has no tendency to fog, even when used with very strong bases like sodium hydroxide, but phenidone and metol do tend to fog, even with carbonates. So, by eliminating the secondary developer, I could also eliminate the restrainer. In fact, catechol and carbonate make a fairly good developer on their own, but lacking a preservative, it oxidizes quickly which encourages general stain. The addition of a tiny amount of ascorbic acid is all that's required to make an excellent acutance developer that works in tanks or trays, with intermittent agitation. The agressive tanning keeps development at the surface, which, combined with the generous staining keeps grain to a minimum and sharpness to a maximum. If sharpness is your first priority, Hypercat is very hard to beat.

Hypercat's closest competitor for sharpness is a concentrated glycin developer:

Distilled water: 50ml
Sodium sulfite: 12g
Potassium carbonate: 75g
Glycin: 10g
Distilled water to 100ml

This concentrate is diluted 1:50-1:200 for intermittent agitation or rotary processing or stand development.

The above developer keeps pretty well (at least 6mos), but an even longer lasting solution could be made by dividing the developer and preservative from the base, into two separate solutions. I like the simplicity of a single solution, and I have always used my stock up before it went bad.

Both Hypercat and the glycin developer above are classic, single-agent acutance developers, one staining and the other non-staining, both produce incredibly sharp negatives.

Vlad Soare

17-Dec-2010, 12:09

Thanks, Jay. It's always a pleasure to read your posts.
To be pedantic, Hypercat has two developing agents - it has ascorbic acid. :p
Just kidding. There's probably not enough of it to act as a reducer. :)

The reason I asked this question is that we (or at least I) often tend to regard developing agents according to the way different developers containing them work, which is not correct. For a person without a solid background in chemistry and/or developer formulation, it's difficult to know just how much of a certain property of a developer is due to each individual agent. That's why I was thinking that in order to compare pyrogallol to catehol one should compare developers containing them as sole developing agents.

Now, one developer based only on pyrogallol is ABC. This gives coarse grain, low film speed (lower than box speed), a pronounced toe (even with T-Max), low general stain, and can build extreme density even with films which are famously reluctant to build density (like HP5+). It also preserves every little detail in the highlights no matter how dense they are. It gives a greenish stain which is almost invisible at first glance, and only evident by direct comparison with an unstained negative. It's not a high acutance developer, but it looks sharp because of the coarse grain (kind of like Rodinal).

Let's see how it compares to Hypercat. Hypercat is a high acutance developer, which ABC is not. It gives good film speed, which ABC does not. It gives fine grain, while ABC does not. There are two points you didn't mention, namely how able it is to build extreme density when need be (for instance, when developing non-TMax films for salt prints), and what the color of the stain is. These two points aside, it looks to me to be quite different from ABC.

But I'm not sure whether this proves anything. OK, they are different, but are these differences due only to pyrogallol versus catehol? Can a developer with all the properties of ABC be made with catehol (and no other agent) instead of pyrogallol? Would Hypercat work the same with pyrogallol (and no other agent) instead of catehol? :confused:
Do you think you could simply replace catehol with pyrogallol in Hypercat without altering any of its properties (at least not significantly)?

sanking

17-Dec-2010, 13:32

To be pedantic, Hypercat has two developing agents - it has ascorbic acid. :p
Just kidding. There's probably not enough of it to act as a reducer. :)

The interesting thing about ascorbic acid is that it does not create any synergy with pyrocatechol. The main purpose of ascorbic is to minimize oxidation and prevent general base + fog stain, which of course serves no purpose.

Ascorbic essentially plays the same role in a pyrocatechol developer as sodium sulfite in minimizing oxidation, and so far as I have determined they are both equally effective in doing so. Pyrocat-HD contains sulfite, and Pyrocat-MC contains ascorbic, but general stain is very low with both, which leads me to believe there is no practical advantage of one over the other. However, if you increase the amount of either ascorbic or sulfite too much you will eventually kill the stain.

However, sulfite plays an additional role in that it actually makes a pyrocatechol developer more energetic, but does so at the expense of the stain. So if you double, triple and quadruple the amount of sulfite in the Pyrocat-HD formula the formula becomes more and more energetic (i.e. faster development times for the same CI), but the stain is decreased.

Sandy

Vlad Soare

17-Dec-2010, 14:17

The interesting thing about ascorbic acid is that it does not create any synergy with pyrocatechol.
That's indeed interesting. I didn't know that. Thanks.

The thing about the activity increasing with the addition of more sulfite is also interesting. Why do you think this happens? One explanation I can think of is that catehol's oxidation by-products might not only stain/tan the gelatin, but also inhibit the development reaction, acting like some kind of restrainer. The more sulfite in the solution, the less by-products (a.k.a. stain) will form, so the less restrained (thus more energetic) the developer will be. But I'm just guessing. Thinking aloud again. Am I close? :)

sanking

17-Dec-2010, 15:02

That's indeed interesting. I didn't know that. Thanks.

The thing about the activity increasing with the addition of more sulfite is also interesting. Why do you think this happens? One explanation I can think of is that catehol's oxidation by-products might not only stain/tan the gelatin, but also inhibit the development reaction, acting like some kind of restrainer. The more sulfite in the solution, the less by-products (a.k.a. stain) will form, so the less restrained (thus more energetic) the developer will be. But I'm just guessing. Thinking aloud again. Am I close? :)

Vlad,

I read the explanation for this a long time ago in one of the tomes by either Grant Haist or Kenneth Mees but can not remember what it was. What you suggest sounds very reasonable and could very well be true, but I would have to do a bit of research to verify this and I don't have the time today.

Sandy

onnect17

17-Dec-2010, 15:48

Sandy,
I have a question regarding the Pyrocat-HD formula. The "Darkroom Cookbook" 3rd ED. lists Solution A with 1g of potassium bromide. In the website (pyrocat-hd.com) is listed as 2g. Anything changed in the formula or is just a typo?

Also PC-TEA is listed in the same book with 0.5g of phenidone, I thought it was 0.25g.
I do not know if Pat Gainer has an account in this forum.

Jay DeFehr

17-Dec-2010, 16:15

Hello Vlad,

You make some interesting points and observations. Another developer that contains only pyro is Pat Gainer's Pyro-TEA, containing only pyro and TEA. How does Pyro-TEA compare to ABC Pyro? Very closely, it turns out, although Pyro-TEA has some important advantages over ABC Pyro, in keeping properties, consistency, and ease of use. But the essential characteristics of Pyro are common to both developers. My goal in formulating 510-Pyro was to retain and maximize the positive characteristics of pyro while minimizing or eliminating its shortcomings, and I think 510-Pyro does that pretty well.

Catechol differs from pyro in some important ways. Catechol tends toward high contrast, while pyro is soft working. This is a generalization, as both developers can be made to do the opposite, but it is generaly true. Catechol requires a higher pH environment to work than pyro does, and is more sensitive to sulfite, ascorbic acid, and bromide than pyro is. Pyro has a much higher reduction potential than catechol does. Catechol has no tendency to fog, even when used with caustic alkali. Regarding the color of the dyes produced by each agent, while they might look different to the eye, their effects on graded and VC printing papers is essentially identical. The reason ABC Pyro's stain is not obvious is because that developer uses a lot of sulfite, restricting the stain to the highest densities, where it's most difficult to see.

An aside: When testing for optimum sulfite/ ascorbic acid ratio, it's remarkably easy to see the effect. Using a stepwedge exposed in a sensitometer, one begins with no sulfite/ ascorbic acid, and the stain can be measured in the base of the film where there is no exposure. Adding sulfite/ascorbic acid, the stain can be seen to retreat up the scale. It is quite possible to choose the exact step of the scale at which the stain begins. I set that point conservatively, to avoid general stain under all conditions, but not nearly as high as it is in ABC Pyro.

I think one could mimic the working properties of ABC Pyro with a catechol-only developer, fairly closely. I'd use a high developer content, like ABC's 6g/liter. That would assure plenty of oompf for building density, and temper the sharpness produced by edge effects of a dilute developer. Then I'd place the stain point high on the scale, to match ABC's, which would increase graininess. To introduce a toe, I'd use a high concentration of carbonate with potassium bromide. Something like this:

1 liter working solution:

Sodium sulfite 2-3g
catechol 6g
sodium carbonate 10g
KBr 1g

I don't think I could make a pyro-only developer behave like Hypercat. I've tried. The best single agent pyro developer I've made is the following:

TEA 75ml
ascorbic acid 6.5g
pyro 13g
TEA to 100ml

The above is a lot more like ABC Pyro than it's like Hypercat. I gave up on it because it didn't do anything 510-Pyro didn't do better. 510-Pyro has proven very resistant to improvement.

sanking

17-Dec-2010, 22:02

Sandy,
I have a question regarding the Pyrocat-HD formula. The "Darkroom Cookbook" 3rd ED. lists Solution A with 1g of potassium bromide. In the website (pyrocat-hd.com) is listed as 2g. Anything changed in the formula or is just a typo?

Not sure how these things get changed. The original Pyrocat-HD formula, which I have never changed, contains one gram of potassium bromide per liter of Stock Solution A.

Now, the fact of the matter is that increasing the amount of bromide to 2 grams per liter will not make a lot of difference, though it will slightly decrease B+F and slightly decrease film speed. And in fact, you could leave it out altogether, which would increase B+F a tad, but also increase effective film speed a tad. But unless you are into sensitometry the differences would not be noticed in either case.

Sandy

Vlad Soare

20-Dec-2010, 01:29

Thanks, Jay. That's very interesting.
I suppose one other way to assess the stain would be to bleach the negative completely, followed by fixing, until all silver is gone and only the stain remains. One could then compare negatives developed in different developers and see just how much of the image is made of stain with each of them. Of course, a step wedge is more accurate, but I think that a real life image might make the whole effect easier to visualize. Maybe I'll try this when I have the time.

Another developer that contains only pyro is Pat Gainer's Pyro-TEA, containing only pyro and TEA. How does Pyro-TEA compare to ABC Pyro? Very closely, it turns out

I don't think I could make a pyro-only developer behave like Hypercat. I've tried. The best single agent pyro developer I've made is the following:

TEA 75ml
ascorbic acid 6.5g
pyro 13g
TEA to 100ml

The above is a lot more like ABC Pyro than it's like Hypercat.
Thanks. This seems to confirm my belief that, while pyrogallol and catehol could be made to simulate similar behaviors by combining them with other developing agents, they behave significantly differently when used on their own. You can add an extra developing agent to compensate for certain properties of pyrogallol or catehol, and thus make one seem similar to the other, but objectively speaking their intrinsic properties are different. At least that's my (admittedly uneducated) opinion, and your observations seem to confirm it.

Jay DeFehr

20-Dec-2010, 12:17

Vlad,

Pyro and catechol share the properties of staining and tanning, but are otherwise quite different agents. Catechol is more similar to hydroquinone, and pyro is more similar to metol than the two are similar to each other. I wonder if anyone has ever tried to make a developer containing both agents? It would be great if the two were superadditive, and we'd have a pairing as versatile as MQ, but with staining and tanning. I wonder what that developer might look like? I think I'll try the following:

TEA 50ml
Pyro 10g
catechol 10g
ascorbic acid 1g
TEA to 100ml

1 liter of 1:100 working solution would contain a gram each of pyro and catechol, with .1g of ascorbic acid as a preservative.

According to Sandy, a 1:100 dilution should have a pH around 9.5, theoretically too low to activate the catechol, in which case, I should expect results similar to Solo. If the developer is more active than Solo, it can only mean the catechol is contributing to development, which suggests some kind of additivity between the pyro and catechol.

I don't think pyro and catechol are additive. If the developer is no more active than Solo, I can raise the pH into the range where catechol is active, and see what happens. The first case is like adding catechol to a pyro developer, and the second is like adding pyro to a catechol developer, as I formulate them, although there is a long history of pyro soda developers pairing pyro with sodium carbonate.

I wonder how a 50/50 blend of pyro/catechol would differ from a 100% of either? It's a pretty dumb idea, but that's never worried me before. Maybe someone else has already tried something like this but are too embarrassed to admit it.:D

Vlad Soare

21-Dec-2010, 05:43

Pyro and catechol share the properties of staining and tanning, but are otherwise quite different agents. Catechol is more similar to hydroquinone, and pyro is more similar to metol than the two are similar to each other.
That's what I thought, too. Thanks for confirming it.

I wonder how a 50/50 blend of pyro/catechol would differ from a 100% of either? It's a pretty dumb idea, but that's never worried me before. Maybe someone else has already tried something like this but are too embarrassed to admit it. :D
Maybe they'd cancel each other out? :p :D

sanking

21-Dec-2010, 07:50

According to Sandy, a 1:100 dilution should have a pH around 9.5, theoretically too low to activate the catechol, in which case, I should expect results similar to Solo. If the developer is more active than Solo, it can only mean the catechol is contributing to development, which suggests some kind of additivity between the pyro and catechol.

The threshold of activation for pyrocatchol used as a sole agent is around 10.9. However, it could be different if used in combination with another agent. One would have to test to determine if there was any activity from pyrocatechol + pyrogallol at pH of 9.5.

But I don't see what purpose could be gained. Both pyrocatechol and pyrogallol are fairly high contrast single reducing agents (at least when used by themselves) that probably need to be combined with a lower contrast agent like phenidone or metol for best result, at least in theory.

Sandy

Sandy

kev curry

21-Dec-2010, 08:20

Jay, do you have any idea of the shelf life of your 510 formula? Thanks.

Bob McCarthy

21-Dec-2010, 09:50

I've been reading this with interest and have one question

Does the fact that we're shooting 4x5 and 8x10 make a difference as to the most appropriate developer? After all grain is a non issue, and edge effects differences are minimal as enlargemant ratio is small.

Do some appear smoother toned??

Ive used standard developers for a long time with success, but interested to try a developer that harnesses highlights better.

bob

Jay DeFehr

21-Dec-2010, 11:46

The threshold of activation for pyrocatchol used as a sole agent is around 10.9. However, it could be different if used in combination with another agent. One would have to test to determine if there was any activity from pyrocatechol + pyrogallol at pH of 9.5.

But I don't see what purpose could be gained. Both pyrocatechol and pyrogallol are fairly high contrast single reducing agents (at least when used by themselves) that probably need to be combined with a lower contrast agent like phenidone or metol for best result, at least in theory.

Sandy

Sandy

Hi Sandy,

I agree testing is called for. There are mechanisms by which the pH threshold of an agent can be lowered. One such mechanism is the induction period, which some claim to be the basis of additivity. I think this is what's going on in Halcyon. I think the PPD decreases the induction period of the ascorbic acid, resulting in a quite active developer that uses only sodium sulfite as an alkali. We know ascorbic acid alone in a sulfite solution won't develop anything, and that PPD alone in sulfite will only develop to a very low contrast with extended development times. The two agents together seem a match made in heaven.

I disagree about the nature of pyro; I don't think it's an inherently high contrast developer. Pyro alone is a soft working developer, building density slowly, but energetically. I don't think pyro developers would be so prized by portraitists, or so famed for rendering delicate highlights and atmospheric effects if they were inherently high contrast developers. Pyro alone in TEA and metol alone in TEA produce remarkably similar results. I used both to develop Tech Pan, with excellent results.

Catechol has more of a split personality. Catechol alone can be used as either a lith developer, a highly compensating developer (Windisch), a low contrast developer (TD3), an acutance developer (Hypercat) or a superfine grain developer in combination with PPD (meritol), or metol (Herman's), or a general purpose developer in combination with several secondary developing agents (Pyrocats). Catechol is very similar to hydroquinone in this way. We don't see metol or pyro used in this variety of ways.

Bob,

My opinion is that the best developer for any person is mostly a matter of taste, and especially so for LF users. I prize gradation above all other other characteristics, but generally strive for the best balance of image qualities. For me, 510-Pyro produces the best overall IQ package of any staining developer I've tested, but this is relative. In absolute terms, I don't think it matters much which developer one uses for LF.

Kev,

The short answer is, I don't know. There was a time when I would have said decades, but I don't think that's true, except possibly in the case of properly mixed concentrate stored in unopened vapor-tight bottles. In use, water inevitably finds its way into the concentrate, thereby shortening its life.

There are several grades of TEA, only two of which are suitable for making concentrated stock solutions: TEA 99%, and TEA 99% Reagent Grade. The RG is ridiculously expensive, leaving only 99% TEA as a practical option. Never use 85% TEA or any LFG (Low Freeze Grade), which contains 15% water. 99% TEA might contain fractional percentages of DEA and/or MEA and/or water. The DEA and MEA are of no concern, but the water can be a problem. It's imperative that the TEA/concentrate be kept in an anhydrous state. Once hydrated, the developer will oxidize until the available water is used up. TEA is mildly hygroscopic, so exposure to air should be kept to a minimum.

Best practices:

Use only 99% TEA

Store in an airless container (I use IV bags)

Use a measuring syringe to dispense concentrate to avoid repeated exposure to air of the concentrate.

Under the above conditions, the concentrate will last at least a few years.

For maximum longevity:

Dry TEA before mixing, in a shallow glass baking dish in the oven at 250F for 1 hour. TEA begins to darken at 140F, but since there's no developer in the TEA, this has nothing to do with developer oxidation and can be ignored.

Dry chemicals in oven before mixing

The critical thing is to keep the concentrate dry. Never dip a wet syringe, or other instrument into your concentrate. Air contains water, so keep it away from your concentrate as much as possible. Under proper storage and dispensing conditions, 510-Pyro will last a VERY long time. Even under very poor storage and dispensing conditions, it will last several months.

kev curry

21-Dec-2010, 15:44

Thanks Jay. I might just have to give 510 a go.

Jay DeFehr

21-Dec-2010, 18:23

Kev,

100 ml of 510-Pyro concentrate goes a long way. I've developed film at dilutions as high as 1:600, and I suspect 1:1000 is possible, as long as 1ml of concentrate is used for each 80 square inches of film. Even at the standard dilution of 1:100, 100ml makes 10 liters of working solution, so you don't need to make much to test it. Let me know if I can be of any help.

Vlad Soare

22-Dec-2010, 01:38

Bob, I don't enlarge too much. I seldom make 12x16" prints, my biggest regular size being 9.5x12". At these sizes, even with 4x5" ASA 400 film, I can see no grain, and the gradations of the tones are as smooth as I can expect them to be.

I once photographed a very detailed subject, in strong lateral light, on three 4x5 sheets of TMY-2. One was then developed in D-76, one in Pyrocat-HD with normal agitation (once every minute), and one in Pyrocat-HD with reduced agitation (once every three minutes, lengthening the total time to get the same CI).
In a 9.5x12" print I could perceive no difference whatsoever.
With the head raised to the top of the column (I think the print size would have been a little over 16x20") I could see a bit of grain if I looked very carefully, but I still couldn't tell the three prints apart.
I then switched to a 50mm lens (I don't know what the print size was, as the image was exceeding the enlarger's baseboard by far). This time I could see a slight difference in the appearance of the grain between D-76 and Pyrocat-HD, though I couldn't call one finer grained than the other. The sheet developed in Pyrocat with reduced agitation seemed to be juuuust barely sharper than the other Pyrocat negative, and both were slightly sharper than the D-76 negative. The differences were small, and only visible by direct comparison.

So, although my test may not have been too scientific and may not be too conclusive, in my opinion the differences in grain and sharpness between developers are subtle, and only visible in big enlargements.

However, graininess and sharpness aside, there are other properties that may be of importance to large format users. One is the ability to preserve fine details in highlight areas. Another one is the ability to build extreme density for alternative processes. Another one is the ability to make dual-purpose negatives, that is negatives suited to silver printing as well as to alternative processes.
Staining developers have an advantage here over non-staining ones.
Also, their tendency of somewhat desensitizing the film is a nice bonus when developing by inspection.
Then there are other practical, non-photographic matters, like keeping properties, cost, ease of mixing, etc., which may or may not be of importance to you, regardless of the format you use.

kev curry

22-Dec-2010, 05:53

Thanks for the kind offer Jay. Cheers!

Fred L

22-Dec-2010, 06:11

One of the best darkroom printers in Toronto had to quit the darkroom because of this....

Henry Yee ?

sanking

24-Dec-2010, 12:05

I disagree about the nature of pyro; I don't think it's an inherently high contrast developer. Pyro alone is a soft working developer, building density slowly, but energetically. I don't think pyro developers would be so prized by portraitists, or so famed for rendering delicate highlights and atmospheric effects if they were inherently high contrast developers. Pyro alone in TEA and metol alone in TEA produce remarkably similar results. I used both to develop Tech Pan, with excellent results.

Jay,

I would be interested to understand your definition of a high contrast developer as it relates to the "nature" of pyrogallol and pyrocatechol. I have carried out numerous experiments using pyrocatechol and pyrogallol as sole reducers in formulas, and in combination with metol, phenidone and other secondary reducers. In almost every instance when pyrogallol and procatechol were used in the same amount (and pH adjusted to optimum for both reducers) I found that film would develop to about the same CI for equal time of development. From those experiments I conclude that pyrogallol and pyrocatechol are quite similar in the way they work and that either can be used to make both low contrast and high contrast developers, and in fact you can find examples of both in Anchell's and Troop's The Film Developing Cookbook.

Sandy

sanking

24-Dec-2010, 14:45

So, although my test may not have been too scientific and may not be too conclusive, in my opinion the differences in grain and sharpness between developers are subtle, and only visible in big enlargements.

However, graininess and sharpness aside, there are other properties that may be of importance to large format users. One is the ability to preserve fine details in highlight areas. Another one is the ability to build extreme density for alternative processes. Another one is the ability to make dual-purpose negatives, that is negatives suited to silver printing as well as to alternative processes.
Staining developers have an advantage here over non-staining ones.
Also, their tendency of somewhat desensitizing the film is a nice bonus when developing by inspection.
Then there are other practical, non-photographic matters, like keeping properties, cost, ease of mixing, etc., which may or may not be of importance to you, regardless of the format you use.

Vlad,

I totally agree with your comments about grain and sharpness. People who change developers because they believe that they are going to get finer grain or higher sharpness are destined to be sorely disappointed.

Most tanning developers are able to develop film with more resolution than non-tanning developers but the difference is not as great as one might think. For example, in comparing a number of pyro staining and tanning developers with traditional developers like Xtol and D75 with high resolution targets (220 lppm chrome on glass targets, and contact printing) all of the pyro developers developed the film to a resolution of about 160 lppm, whereas the traditional developers maxed out at about 125 lppm. 200 lppm was the theoretical limit for the films, which were Acros and Tmax-100. But the fact of the matter is that very few camera systems are capable of recording even 125 lppm on film so the difference does not matter for LF.

But sharpness is more than resolution, it is a subjective impression of two objective criteria, resolution and acutance, and acutance is determined as much by dilution and type of agitation as by the developer itself. For example, at a 1+1+50 dilution with rotary development Pyrocat is not acutance developer, but at 1+1+100 and intermittent agitation it is indeed an acutance developer, and at 1+1+200 and minimal agitation it becomes a very high acutance developer, and with divided development the acutance is higher than with any other developer I have ever tried.

Grain is another issue. With rare exceptions (Rodinal for example) about 99% of grain appearance is determined by the film and not the developer. If you want finer grain the best way to get is change film because there is no developer out there that will make Tri-X look like Fuji Acros. And almost without exception, if you get finer grain with a given film with one developer it is almost certainly at the expense of acutance.

Is there any inherent difference in sharpness and grain between the various pyro staining and tanning developers? In my opinion there is not, and I have carefully tested most of them. I have made a 40"X60" digital inkjet print from an original 6X7 cm Mamiya 7II negative developed in Pyrocat-HD that has stunning sharpness and no visible grain. The negative was scanned at 5080 spi with a high end scanner. Could someone have done better with another developer and film in terms of grain and sharpness? I seriously doubt it, after all no grain at a print size of 40X60" is pretty hard to beat. On the other hand someone might have matched the results with another pyro staining and tanning developer. So if you find anyone out there who claims that a particular pyro staining and tanning formula is both sharper and has finer grain and higher film speed than others watch out because that person is just blowing smoke up your a*s. Not that anyone has done that in this thread, just saying.

An issue about grain that has not been mentioned is that the rules are not the same when scanning as when developing print in the wet darkroom as there are a wide range of results depending on the scanner, the skill of the operator, and whether the negative was fluid mounted or not.

That said, there are indeed some inherent differences between formulas that one might find advantageous. For example, PMK is a very good developer in trays, and it can be adapted to work well in rotary processing as well, but why bother when there are several other good pyro formulas that work great out of the box in rotary processing. Another difference would be if the developer is mixed in glycol or TEA, which will give much longer shelf life. Still another consideration would be two part developers like PMK, WD2D and Pyrocat-HD, -MC versus one part solutions like 510-Pyro or my Pyro Uno formula. Another consideration would be does the formula work well with divided development.

Sandy

onnect17

24-Dec-2010, 18:59

Sergio,
I'm not familiar with the availability of chemicals in Bogota or how easy could be to place an order from outside the country. In any case, the SBR obtained from pyrocat-hd divided is amazing. Sandy helped me to find the right concentration and I developed some 35mm for testing. Check this sample, exposed for the shade and still you are able to see the white tower blasted by the sun in the background. Not adjustment was made, just invert.
Armando

I want to start developing with pyro. I am currently using 4x5 with FP4 and Fomapan 100. Will probaby open the repertoire to HP5 and that will be it at least for some time until I get a better feel for film again.

Sorry if this has been done to death here, but there is so much info on pyro that it is difficult to filter out. I am not a novice in the darkroom and have some experience mixing my own stuff, and I know how to handle chemistry and so on. But I have never used pyro and I closed my darkroom 8 years ago. Now i want to at least develop my film and scan afterwards. Maybe I'll start doing some contact printing which I guess is as far I can go in making prints at home with no darkroom. It has got to be airline friendly since I will fly it in the luggage. Which recipe do you think is best for my needs? What are your suggestions and advice on this topic? Thanks in advance. :)

Jay DeFehr

24-Dec-2010, 19:59

Jay,

I would be interested to understand your definition of a high contrast developer as it relates to the "nature" of pyrogallol and pyrocatechol. I have carried out numerous experiments using pyrocatechol and pyrogallol as sole reducers in formulas, and in combination with metol, phenidone and other secondary reducers. In almost every instance when pyrogallol and procatechol were used in the same amount (and pH adjusted to optimum for both reducers) I found that film would develop to about the same CI for equal time of development. From those experiments I conclude that pyrogallol and pyrocatechol are quite similar in the way they work and that either can be used to make both low contrast and high contrast developers, and in fact you can find examples of both in Anchell's and Troop's The Film Developing Cookbook.

Sandy

Hi Sandy,

A developing agent suitable for use in a high contrast (lithographic-type) developer should work in a very high pH environment without fogging, and exhibit a high sensitivity to bromide. Catechol does this, but pyro doesn't; hydroquinone does, but metol doesn't. Pyro and metol are too soft working to be used in a high contrast developer. All these agents can be used to make negatives of pictorial contrast. I hope this clarifies my comparisons of catechol to hydroquinone and metol to pyro.

Regarding grain, I don't take as hard a line as you do. While making Tri-x look like Acros might be a stretch, some developers can make TMY look like TMX, or Tri-X look like Plus-X, and that's significant.

Grain and sharpness don't differ enough among developers to be very meaningful for LF work, but the same cannot be said for smaller formats. It stands to reason the best developer for small formats should be more than good enough for larger ones. Film and format are far more important than developer.

sanking

24-Dec-2010, 20:01

Is there any inherent difference in sharpness and grain between the various pyro staining and tanning developers? In my opinion there is not, and I have carefully tested most of them.

Sandy

I should have qualified that statement by excluding old-time formulas such as ABC Pyro. This is an excellent formula for LF film but gives lower film speed and more pronounced grain than contemporary pyro formulas. At least the grain is fairly pronounced when using fresh sulfite. If the sulfite is old there will be more stain and this will reduce the appearance of grain considerably, but with much greater B+F or general stain, which will also reduce sharpness.

Sandy

sanking

24-Dec-2010, 20:26

Hi Sandy,

A developing agent suitable for use in a high contrast (lithographic-type) developer should work in a very high pH environment without fogging, and exhibit a high sensitivity to bromide. Catechol does this, but pyro doesn't; hydroquinone does, but metol doesn't. Pyro and metol are too soft working to be used in a high contrast developer. All these agents can be used to make negatives of pictorial contrast. I hope this clarifies my comparisons of catechol to hydroquinone and metol to pyro.

Regarding grain, I don't take as hard a line as you do. While making Tri-x look like Acros might be a stretch, some developers can make TMY look like TMX, or Tri-X look like Plus-X, and that's significant.

Grain and sharpness don't differ enough among developers to be very meaningful for LF work, but the same cannot be said for smaller formats. It stands to reason the best developer for small formats should be more than good enough for larger ones. Film and format are far more important than developer.

Jay,

OK, but from what you write I would conclude that pyrocatechol is simply a more versatile reducer than pyrogallol. It can be used in both low contrast and high contrast formulas,as well as in lith developers. But for pictorial use both pyrocatechol and pyrogallol can be used in both low contrast and high contrast formulas.

As regards grain and sharpness, most of my work these days is with medium format (and I print fairly large), so I have looked very carefully at the grain and sharpness characteristics of most of the contemporary pyro developers. There is almost no difference between any of them, and when there is an advantage to grain or sharpness, if you make a good comparison, you will find that a plus to grain means a slight negative for sharpness, and vice versa.

It would be nice if some independent body would do a comparison test of these developers, but in the absence of such people will come to their own conclusions and, as it were, vote with their money and time.

Sandy

JMB

24-Dec-2010, 20:35

Hypercat

A
Propylene Glycol 75ml
ascorbic acid 1g
catechol 10g
PG to 100ml

B
Sodium carbonate 20%

Dear Jay,

What is the function of the propylene glycol?

Thank you and Merry Christmas

Jay DeFehr

24-Dec-2010, 21:07

Sandy,

I would agree catechol is more versatile than pyro, but I don't think it's so simple. Pyro can do things catechol can't do as well, or in the same way. Pyro works at a lower pH and is less sensitive to the stain-killing effects of preservatives, so it doesn't oxidize as quickly, and lasts longer in a tray. Staining pyro developers can be formulated to produce finer grain than staining catechol developers. Pyro can be made as a single solution developer. Most importantly, pyro produces better gradation than catechol.

I too have tested most contemporary staining developers, and I disagree with your conclusion regarding grain and sharpness. If sharpness is the combined subjective effect of resolution and acutance, a finer grained print of higher resolution will appear as sharp as a lower resolution, grainier print of higher acutance. I think scanning favors resolution over acutance.

I don't care which developer anyone uses. Developer formulation is interesting for me, and I enjoy discussing the subject with others who share my interest. If something useful comes out of these discussions, all the better, but I don't crave arbitration or consensus. Developers are interesting, but not important.

Jay DeFehr

24-Dec-2010, 21:12

Hypercat

A
Propylene Glycol 75ml
ascorbic acid 1g
catechol 10g
PG to 100ml

B
Sodium carbonate 20%

Dear Jay,

What is the function of the propylene glycol?

Thank you and Merry Christmas

The Glycol is the solvent, and takes the place of water in a standard formula. The use of glycol permits the formulation of a developer with very low preservative content while simultaneously and significantly extending the shelf life of the concentrate.

To be clear, the formula is for a concentrated stock solution that is diluted with water to make a working solution. 1+5+94 (1:5:100) is a standard dilution.

Merry Christmas!

onnect17

24-Dec-2010, 21:28

Jay DeFehr

24-Dec-2010, 21:37

Armando,

I think Sandy and I are more than familiar with these developers and so there's little to be gained by your generous offer. If your curious about the differences, you should test for your own benefit. Let me know if I can be of any help.

onnect17

24-Dec-2010, 21:57

Sure, Could 1:100, 6 mins at 68F be a good starting point for 510-Pyro in the rotary?

Armando,

I think Sandy and I are more than familiar with these developers and so there's little to be gained by your generous offer. If your curious about the differences, you should test for your own benefit. Let me know if I can be of any help.

sanking

24-Dec-2010, 22:03

[QUOTE=Jay DeFehr;664745]

Hi Jay,

I don't agree with much in your previous post. It is your opinion but definitely not substantiated as fact. I respect your knowledge and experimentation, but I don't respect when you state opinion as fact. And frankly, much of what you state as fact is absolute nonsense, and I refer specifically to your comment that pyrogallol does not oxidize as quickly as pyrocatechol. In fact, the absolute opposite is true and you could easily verify this by using both as a sole reducer. Have you ever made that test? If not, please do so and report the results. Here is what Bill Troop (in The Film Developing Cookbook, p. 79) says about pyrocatechol. "Pyrocatechin (also called catechol, pyrocatechol, and catechin) stains and tans as well as pyro. It is generally considered to be more stable and reliable. It has been used in a few commercial developers such as Neofin Blue and even, for a brief period, in HC 110." Does Bill Troop's opinion matter? Well, I think so as he is without doubt one of the most brillant minds in the world re: photographic chemistry.

The fact that you don't want either arbitration or consensus pretty much says it all as far as I am concerned. Sorry, but if you plan to continue to claim that 510-Pyro is the best staining and tanning developer in the world, you better plan to back it up with independent and objective testing. I have never made such a claim about my formulas, nor has Gordon Hutchings or John Wimberely. Both do great work with their formulas, as I do with mine, but as for the best formula I have never made and will never make such an absurd claim as to the best pyro developer. You should not either unless you are prepared to have your formula(s) compared with independent and objective comparison to others of its type. Even then, do you think anyone would care since by your own words developers are "interesting but not important."

Sandy

Jay DeFehr

24-Dec-2010, 22:11

sanking

24-Dec-2010, 22:31

Armando,

Testing developers against one another requires a very high degree of precision, because the differences are so small. For your results to be meaningful, you'll have to do an awful lot of testing, starting with testing for contrast, so that you can match the two developers. It's a devilishly tedious process, and few home dark rooms are equipped for it, and even fewer lab workers trained for it. How do you intend to measure contrast?

True, but if you use BTZS type testing, with a light integrator or sensitometer, the parameters re: contrast can be narrowed fairly quickly. From my perspective determining contrast is the least of the problems in comparing developers. The much larger issue is how to evaluate grain and sharpness since these are largely subjective issues, and depend also on many post development issues, i.e. whether you print in the wet darkroom or scan to print digitally, what type of scanner you use, how you use it, etc. etc.

Sandy

sanking

24-Dec-2010, 22:52

Sandy and Jay,
I have some tmax 100 35mm I can use for testing Pyrocat-HD and 510-Pyro. Your guys are more than welcome to suggest temperature and developing time for a jobo. I can post a link to the raw images for discussion.
You can pick the scanner: Nikon CoolScan V ED, Imacon 343 or Howtek 4000.
Armando

Armando,

First, you are free to do your own testing and report the results. You don't need my permission, or that of Jay. But I will be happy to assist you with development information. I have good rotary development data for both Pyrocat-HD and 510-Pyro and would be happy to provide it to you, which would eliminate the contrast issue. My data is derived from BTZS testing and is highly portable, "if you are able to replicate exposure and development conditions."

I would welcome independent and objective comparison. Your tests and observations will not be the end all on this issue, but they would be an interesting first step.

Sandy

onnect17

24-Dec-2010, 23:01

onnect17

24-Dec-2010, 23:32

Sandy,
You can save me some time with this information. What development time and temperature do you recommend to use with pyrocat-hd in rotary (one bath) as a starting point. Again, I will adjust it to get the gray card on density .75
Thanks
Armando

Armando,

First, you are free to do your own testing and report the results. You don't need my permission, or that of Jay. But I will be happy to assist you with development information. I have good rotary development data for both Pyrocat-HD and 510-Pyro and would be happy to provide it to you, which would eliminate the contrast issue. My data is derived from BTZS testing and is highly portable, "if you are able to replicate exposure and development conditions."

I would welcome independent and objective comparison. Your tests and observations will not be the end all on this issue, but they would be an interesting first step.

Sandy

Jay DeFehr

25-Dec-2010, 00:13

Sandy,

It seems you're upset. I don't appreciate your tone. I've been very respectful and don't deserve your snide comments. Your nastiness aside, it seems you don't read my posts very thoroughly. I wrote:

Pyro works at a lower pH and is less sensitive to the stain-killing effects of preservatives, so it doesn't oxidize as quickly, and lasts longer in a tray.

I assumed you're familiar enough with developer formulation to understand that since pyro is less sensitive to preservatives, more can be used, and the resulting developer is thereby better preserved. I have tested this, over and over, my results are consistent, and I stand by my statement.

My statement about arbitration and consensus should be taken as my disinterest in making developer formulation a competition. I think your statement about mine says it all, about you. I don't know why you've turned so hostile. Not only do I not plan to continue claiming 510-Pyro is the best staining and tanning developer in the world, but I plan to continue having never made such a ridiculous claim. Where do you come up with this stuff? And what do you mean by, "..you better plan to back it up..."? Who do you think you are?

Sane, rational people understand that users have different priorities in their image making, and so no one developer can possibly be best for all users. If I say, 510-Pyro is the best staining developer I've ever used (I can't remember ever having done so), what can possibly be understood by that? Only the most naive or unbalanced reader could interpret that to be meant as an unqualified absolute, even out of context. I can find pages of examples of my postings in which I describe in detail the compromises involved in developer formulation, and why, in concrete terms, there is no such thing as a best developer. Your reading is paranoiac, at best. Your insistence on grouping yourself with Troop, Wimberley, and Hutchings, opposed to me, is just pathetic, I'm sorry to say. You're taking all this WAY too personally. These are only developers, and just not very important, and no, I don't think anyone cares, except for you.

In truth, I don't really think you care, either. It seems you just don't like to be disagreed with, no matter how respectfully. Why do you always have to ruin these discussions, when you have so much to offer?

Other posters,

I'm sorry for my part in the degeneration of this interesting thread. I hope everyone enjoys the holidays in good health.

Jay DeFehr

25-Dec-2010, 00:34

Jay,
I understand that my test is quite limited and subjective but it will be the same for all the developers.
First, I prepare a target. Could be a few step wedges with at least 21 bars and gray card to meter, all illuminated by a 4700K lamp. Expose one or more rolls to the same target. I use 4 or 5 exposures for each developer.
The Jobo cpe2 is ok if I use the color thermometer, which gives 0.2C accuracy. Should be enough.
I process the film following the recommendations for the developing time and temperature and measure density in the step wedge (help to calculate the CI).
If possible change the time and temp to place the gray card close to density 0.75.
Then visually compare the samples for sharpness, grain and accutance.
Scan the negatives as positive in color. Evaluate again the same parameters per channel.
Armando

Armando,

I'm not trying to be coy, or evasive. It really is painfully demanding to generate credible data comparing developers in a home darkroom. Even if you were to generate data for grain (are you going to do an RMS granularity test, or just a subjective evaluation?), sharpness (do you have a microdensitometer, or will you evaluate subjectively?), stain (color densitometer?) and film speed (Sensitometer?), there's no way to quantify arguably the most important characteristic; gradation. My point is, no matter what numbers you come up with, someone will find a problem with your methods or your experimental design anyway, and you'll be left with a subjective evaluation. For my part, I don't care one way or the other if you test, or not, or which developer you prefer. I formulated 510-Pyro for my own use, and I've been very happy with it. If you like it too, enjoy. If you'd rather use something else, enjoy. I mean that very sincerely. I do this for fun and nothing more, and I'm not eager to get into another nasty confrontation over something as unimportant as a film developer. If I had data for TMX at hand, I'd happily share it, but I'm at work in Alaska at the moment, and don't have access to that data. Best of luck, and happy holidays.

sanking

25-Dec-2010, 09:08

Jay,

Instead of blaming me for the degeneration of this thread you might consider the nature of your own participation on this forum. You were absent from LF forum for two or three years and during that time I don't recall even one thread on pyro that was confrontational.

Yes, I am irritated with this exchange, not because I don't like to be disagreed with but because I don't like it when people state opinions as fact, and when they use selective information to prove a point, and when they argue points incessantly. But why should I bother to discuss anything with you because you always insist on having the last word? So I will just concede that pyrogallol is a soft working developer and that pyrogallol is much superior to pyrocatechol and be done with any more discussion with you.

Have a Happy Holiday, Jay

Sandy

sanking

25-Dec-2010, 09:32

onnect17

25-Dec-2010, 11:19

Armando,

For what film (s) would you like the data?

Sandy

Sandy,
I'll use t-max 100 (tmx) in 35mm.
Thanks,
Armando

Jay DeFehr

25-Dec-2010, 11:21

Sandy,

In the past, I've written things I regret, and I've apologized for it. Nothing I've written here since then has been disrespectful, but I feel honesty is important, and I believe we're all entitled to rebuttal when we're made the object of personal attacks in a public forum. I've apologized to the other posters in this thread for my part in this unfortunate turn, but I don't owe you any apologies. I've been respectful in my posts and have honestly stated my position to the best of my ability. Reasonable people can navigate the conventions of opinion without the irksome necessity of qualifying every statement, and who doesn't use selective information to make a point?

My opinion of the relative merits of pyro vs catechol are more nuanced than your own, as I've tried to elaborate in this thread. I don't believe either is categorically better than the other, and I don't see how you could have inferred that, unless you read very selectively, and with a strong bias.

Lastly, I'm not surprised no one challenged you on the subject of staining developers in my absence, and so I'm not surprised there have been no confrontations. This thread illustrates that dynamic perfectly, and anyone can read it for themselves. In the final analysis, all I did was to make statements in a respectful and honest manner with which you disagree, and for that you attacked me. I can live with that, but let's not pretend it is otherwise.

Be well, safe travels, and merry Christmas,

Jay

onnect17

25-Dec-2010, 11:55

Jay,
I'm not in the business of rating any film nor creating any film championship or declare any a winner. I was just offering my feedback.
There is not magic film developer, but we can find the pros and cons of each one and use them to our advantage.
Not rush, when you’re back at home send me anything you have about 510-pyro, including any notes and recommendations related to development. I’ll appreciate it. And remember, any of my observations are just that. I’m not planning to go back and question any of your statements regarding the developer.
And happy holidays to you too!
Regards,
Armando

Armando,

I'm not trying to be coy, or evasive. It really is painfully demanding to generate credible data comparing developers in a home darkroom. Even if you were to generate data for grain (are you going to do an RMS granularity test, or just a subjective evaluation?), sharpness (do you have a microdensitometer, or will you evaluate subjectively?), stain (color densitometer?) and film speed (Sensitometer?), there's no way to quantify arguably the most important characteristic; gradation. My point is, no matter what numbers you come up with, someone will find a problem with your methods or your experimental design anyway, and you'll be left with a subjective evaluation. For my part, I don't care one way or the other if you test, or not, or which developer you prefer. I formulated 510-Pyro for my own use, and I've been very happy with it. If you like it too, enjoy. If you'd rather use something else, enjoy. I mean that very sincerely. I do this for fun and nothing more, and I'm not eager to get into another nasty confrontation over something as unimportant as a film developer. If I had data for TMX at hand, I'd happily share it, but I'm at work in Alaska at the moment, and don't have access to that data. Best of luck, and happy holidays.

onnect17

25-Dec-2010, 12:09

Sandy and Jay,
With sadness I’m seeing your guys going after each other like children, so please stop being confrontational. The members of this forum deserve more than that, especially when both can help so much with your experiences. Life is a lot bigger than a film developer formula.
I hope your guys put the ego aside and continue to help.
Happy holidays to both and take a lot of pictures! :)
Regards,
Armando

sanking

25-Dec-2010, 12:28

Sandy,
I'll use t-max 100 (tmx) in 35mm.
Thanks,
Armando

Armando,

Assuming you want to develop your Tmax-100 film to an DR of about 1.35 I would recommend for 510 Pyro about ten minutes of development at 72F with the 1:100 dilution, with continuous agitation in tubes or drum.

Ironically I don't have any good data on Tmax-100 in Pyrocat-HD, but I think you will come close to the same DR with 12 minutes at 72F with the 1+1+100 dilution.

That said, I don't believe you will get best results with either of these developers with rotary development because acutance will be lower than with intermittent and minimal agitation, for sure with Pyrocat. On the other hand, if you plan to scan to evaluate the negatives acutance probably won't matter all that much anyway.

I agree with Jay that making meaningful comparisons of developers is very complicated. At one point in time I considered making an exhaustive study of several traditional developers verus several pyro staining developers but abandoned the project for two reasons, 1) it was too complex and would have taken up tons of time to do right, and 2) in the end the study would have served no useful purpose and would most likely have created more arguments and controversy and solved nothing.

On the other hand, individual comparisons of the type you propose are interesting because they offer objectivity. So I kind of see it like this, I prefer real good wine, but sometimes any wine is better than no wine at all.

Sandy

Jay DeFehr

25-Dec-2010, 13:28

Armando,

I agree completely. I don't think film developers are very important, but I think public civility, and decency are. It has nothing to do with ego, and I resent your suggestion that it's childish to expect courtesy. As I've said, I don't care which developer anyone uses, or even that anyone agrees with me in general, or on any specific point, but I do expect common courtesy. I've stated repeatedly throughout this thread my thoughts on the importance of developer choice (not very important), and I have not argued that one developing agent is better than another, just that there are differences. I've done my best to be clear and concise in describing these differences. The OP asked our opinions about the best staining developers, and I offered mine, with qualifications. Why should any of this offend anyone?

Regarding your proposed test, it came at a point in the thread that made it seem as if you were offering to be an independent arbiter to settle the disagreement between Sandy and me. I simply meant to say that's not necessary, because Sandy and I are both more familiar with these developers than you could possibly be after your test, no matter how well executed, and more importantly, because there's no objective value to a subjective test, except to the tester. But, if you prefer any wine to no wine, you can look at John Finch's comparison of 510-Pyro and Pyrocat HD in The Art Of Black And White Developing. I contributed to that test in no way. Finch concluded that 510-Pyro was both sharper and finer grained than Pyrocat HD, a claim I've never made. So, even if your test showed the opposite result, it would become a debate about testing itself, and not about the developers. The whole idea of an independent tester is rather absurd, for all these reasons. I suggest you stick with Pyrocat HD, since it gives you satisfying results, and don't waste your time with pointless testing.

Merry Christmas!

onnect17

25-Dec-2010, 13:39

onnect17

25-Dec-2010, 13:46

Armando,

Assuming you want to develop your Tmax-100 film to an DR of about 1.35 I would recommend for 510 Pyro about ten minutes of development at 72F with the 1:100 dilution, with continuous agitation in tubes or drum.

Ironically I don't have any good data on Tmax-100 in Pyrocat-HD, but I think you will come close to the same DR with 12 minutes at 72F with the 1+1+100 dilution.

That said, I don't believe you will get best results with either of these developers with rotary development because acutance will be lower than with intermittent and minimal agitation, for sure with Pyrocat. On the other hand, if you plan to scan to evaluate the negatives acutance probably won't matter all that much anyway.

I agree with Jay that making meaningful comparisons of developers is very complicated. At one point in time I considered making an exhaustive study of several traditional developers verus several pyro staining developers but abandoned the project for two reasons, 1) it was too complex and would have taken up tons of time to do right, and 2) in the end the study would have served no useful purpose and would most likely have created more arguments and controversy and solved nothing.

On the other hand, individual comparisons of the type you propose are interesting because they offer objectivity. So I kind of see it like this, I prefer real good wine, but sometimes any wine is better than no wine at all.

Sandy

Sandy,
Thanks for numbers, I'm running to where the inlaws right now. But tonight I will get with some questions.
Merry Christmas!
Armando.

Gem Singer

25-Dec-2010, 13:50

Hey guys,

"peace on earth and good will toward man"

Why don't y'all go to a neutral corner and cool off. At least until the rest of us have had an opportunity to enjoy the "comfort and joy" of the Christmas holiday.

Thank you for your kind consideration.

Jay DeFehr

25-Dec-2010, 14:59

Jay,
Don't take it personal, I was just trying to make a point how easy we can get out of focus in dialogs as imperfect humans, me in first place. But let's move on, I definetily will look for John's Finch writing.
Looking for the next developer is not such a bad thing. After all that's why I heard of pyrocat and 510-pyro.
And Merry Christmas to you too, and Julie. I hope she's does not bitch like my wife about how much time I spend with the "photography stuff" :)
Regards,
Armando

Well said, Armando, and point taken.

Julia is a tireless advocate of my photography, and film photography in general, and I can't work enough for her. She has no interest in digital photography, and would join the film hoarders if I would.

Merry Christmas to you and your Mrs.!

Michael A. Smith

25-Dec-2010, 16:41

This is one of the rare threads I have read in a long time.

I must admit that I do not understand the need for testing--as long as one understands exposure/development relationships. And I would assume that, more or less, those reading a thread like this would (or should) know exposure/development relationships as readily as they can count from one to ten

My recommendation is to pick a developer--any developer--based on your reading here or on anything else. Then go expose film and make prints. If the negatives are not right and you cannot get a satisfactory print--and you understand exposure/development relationships--you will know what corrections to make for the next time.

And if the photographs do not come out--so what! At least you will have had the pleasure of making photographs.

And don't change your developer or film or paper unless you are unsatisfied with your work. If you are unsatisfied, then try something else. But by all means make pictures.

I have seen too many aspiring photographers spend far too much time making tests--of film, developers, paper, etc.--or testing cameras and lenses. A few of them never get around to really making pictures.

I understand that the more scientifically minded above us may get more pleasure in the testing procedures than in the making of meaningful photographs, and if anyone reading this fits into that category--well then, by all means continue to do what brings you the most pleasure. But for those who aspire to make meaningful photographs, consider doing any testing only after you are dissatisfied with the results you are getting.

As stated previously in this thread, there are no magic developers. The magic is in one's vision.

Michael A. Smith

CP Goerz

25-Dec-2010, 17:04

Yep, I 'used to' test and test all the time! Each 'new' developer was tried, I'd shoot the grey card in light/shadow getting the time temp exactly right, developing the roll of film as if I was assembling an A bomb.

Then the Pyro book came out and I mixed some up.... and then never, ever tested another roll/sheet of film again. All of a sudden I was getting exactly what I wanted in terms of highs/lows and sharpness. I did dabble with a touch of Amidol from time to time but the PMK formula 'as-is' is perfect for me. Photography is sooo much more fun now that I don't have to test and test and test.

Jay DeFehr

25-Dec-2010, 17:09

Michael,

I agree completely.

Merry Christmas!

sanking

25-Dec-2010, 17:27

Michael,

You make some good points, but it should be pointed out that the magic of vision is not mutually incompatible with film testing. I enjoy film testing as a practical and intellectual curiosity but people who have seen my work have never questioned my vision.

I agree completely about learning a developer and sticking to it. I have only used seriously four developers in my entire career as a photographer, DK50 and D76 for the first fifteen years, PMK from the time it came out around 1990 until the late 1990s, and Pyrocat since 1998. I have tested many other developers out of curiosity and while many had some interesting characteristics I never felt that any of them would improve the quality of my negatives. On the other hand I am confident that I could adapt to a a number of other pyro and/or non pyro developers if for some reason I was forced to switch.

And for that matter, I could be just as happy working totally with digital if I could get the same quality for the price as with film because ultimately I am much more about the final print than how I get there, though process is interesting. In fact, I am going to Tunisia for a few weeks in January and am considering going all digital just to see what I can achieve with this Gigapan Epic 100 device and a Lumix GF-1 IR converted 12 mp camera. Won't have to worry about traveling with film and I will be able to process all of my files on the road and upload them in real time.

Sandy

sanking

25-Dec-2010, 21:07

Some of you may not remember the pyro wars that ended in 2007, or you may remember and don’t care. I remember them very well and they were a source of personal misery, and IMO Jay DeFehr was one of the primary persons responsible for those wars. Jay left the forum for a couple of years and there have been no more pyro wars. Now he is back, and I can see where this is heading, and I don’t like the bearing.

I am also very disappointed in some of the comments made in response to the exchange between Jay and me. I have contributed some thousands of messages to this forum, nearly all of them informative and without controversy I am very much resent having the exchange referred to as childish, and that I should go sit in a corner while some enjoyed their Christmas spirit. This, as much as the exchange with Jay, convinced me that I am wasting my time since what I say seems to be so little appreciated.

Finally, I have a serious health issue that has required a lot of radiation therapy, and other treatment, and I don’t need the additional stress created by these types of exchanges.

For all of the above reasons I have decided that I will no longer participate in any threads on pyro developers on this forum. I am sick of the conflict and what was once a source of great pleasure for me has become an albatross.

So there it is. Say what you like, think what you like, but it won’t matter a bit to me. I have made my decision and that is that.

Sandy

Andrew O'Neill

25-Dec-2010, 21:25

Finally, I have a serious health issue that has required a lot of radiation therapy, and other treatment, and I don’t need the additional stress created by these types of exchanges.

Stress is a very bad thing. I hope everything will be okay for you, Sandy.
I hope that you continue contributing here as I (and many others!) have learnt a lot from you over the years here, as well as at your carbon forum.

Cheers!!

Andrew

onnect17

25-Dec-2010, 22:35

Sandy,
Forgive me if you felt insulted in any way for my comments and my poor choice of words but this is exactly what I was trying to avoid. I can imagine how the body reacts to such a aggressive medical treatment and you and your love ones are aware how edgy you are being. It just means you are human.

Now, your guys in more than one occasion transformed a disagreement around a technical issue in a personal exchange, for no reason, and it takes two to tango and you should avoid it.

I think you should not abandon the topic knowing how many people are being help with your comments. Esa no es la actitud de un maestro.

Changing the subject. Do not make the mistake of travelling with only digital gear.
It does not feel the same. Grab at least a 35mm as a backup and a shield-bag for the airports.

I have a little Netbook I use only for travel and you’re more than welcome to borrow it for Tunisia. It’s very small and convenient for travel and you do not have to worry if you lose it on the trip.

I hope to continue to read your posts in the forum and keep in touch, even from Tunisia :)

Regards,
Armando

Some of you may not remember the pyro wars that ended in 2007, or you may remember and don’t care. I remember them very well and they were a source of personal misery, and IMO Jay DeFehr was one of the primary persons responsible for those wars. Jay left the forum for a couple of years and there have been no more pyro wars. Now he is back, and I can see where this is heading, and I don’t like the bearing.

I am also very disappointed in some of the comments made in response to the exchange between Jay and me. I have contributed some thousands of messages to this forum, nearly all of them informative and without controversy I am very much resent having the exchange referred to as childish, and that I should go sit in a corner while some enjoyed their Christmas spirit. This, as much as the exchange with Jay, convinced me that I am wasting my time since what I say seems to be so little appreciated.

Finally, I have a serious health issue that has required a lot of radiation therapy, and other treatment, and I don’t need the additional stress created by these types of exchanges.

For all of the above reasons I have decided that I will no longer participate in any threads on pyro developers on this forum. I am sick of the conflict and what was once a source of great pleasure for me has become an albatross.

So there it is. Say what you like, think what you like, but it won’t matter a bit to me. I have made my decision and that is that.

Sandy

sanking

26-Dec-2010, 15:34

Armando,

You are absolutely correct in that technical discussions should not morph into personal issues. I apologize for my part in that to Jay DeFehr and to others who have followed this thread.

That said, I must stand by my decision to stay out of discussions about pyro developers. In addition to the reasons I have already mentioned I have a number of writing projects that have been on hold for much too long and I need to get to them. The forums are a distraction from that work, and from my own creative carbon transfer printing, and I feel that I need to devote more of my time to the things that really matter to my life.

Thank you for the offer of a netbook, but in fact I already have a HP netbook, and a Blackberry witha data plan that works in foreign countries, so I should be covered pretty well as far as keeping in touch goes.

Sandy

Bob McCarthy

26-Dec-2010, 18:42

Sandy, you've contributed much to the discussions over the years I've been here. It would be a shame for you to go dark in the very area where you've contributed so much.

People can be unintended annoying on occasion.. Those you can not agree or deal with, just ignore them would be my recommendation.

It would negatively impact the community if you went silent.

Very sorry to hear about your health issues, best wishes for a speedy recovery.

Bob

Pawlowski6132

27-Dec-2010, 06:36

I rarely read any reference to the old ABC Pyro formula. I use this. Is it out of style? Why? I don't use TMAX films.

Vlad Soare

27-Dec-2010, 09:41

I believe ABC is rarely mentioned because it's rough by today's standards. It gives low film speed, coarse grain, a pronounced toe (even with films that don't usually have one, like TMY), it's made of three separate solutions, it must be used immediately after mixing because it's dead in half an hour, the amount of stain is very dependent on the freshness of solution B (which has a short shelf life compared to other modern developers), and it's not suited to rotary development because it oxidizes very quickly.
It works fine with large format film intended for contact printing, and I do use it, too, but it's not what I would use with 35mm, or even with medium format.

Jay DeFehr

27-Dec-2010, 11:22

I rarely read any reference to the old ABC Pyro formula. I use this. Is it out of style? Why? I don't use TMAX films.

It's not that ABC Pyro has gone out of style as much as it's been superseded, but like so many other things that have been superseded, it works just as well as it ever did, and is just as capable of making good negatives. If the problems inherent to that formula are not a problem for you, it might not be worth your time and effort to switch to a more modern developer. Problems with ABC Pyro that are addressed by more modern formulas include:

3 stock solutions that age at different rates (keeping properties), which leads to inconsistent working solution characteristics as the stock solutions age, and the general complication of making and using 3 stock solutions.

Low film speed

Coarse grain (in formats/ work flows for which grain is an issue)

Low image stain (fresh solution) and high general stain (with aged stocks)

If none of the above issues are problems for you, there's no need to consider another developer. Choice of film developer is not very important for LF workers, and any disadvantages inherent in a developer can be compensated for or worked around, to some extent.

As a point of interest, the problems with ABC Pyro are typical of the kinds of problems that led to the widespread abandonment of pyro developers in favor of MQ developers. I think those who did so threw the baby out with the bathwater. The evolution of pyro staining developers proceeded mostly along the lines of adding a secondary developer (usually metol), as in Kodak D-7. Very few staining pyro formulas actually exist. Some were formulated to be used undiluted and freshly mixed (Kodak SD-1), and others, like Morley Baer's, were variations on the ABC theme, mixing the pyro from powder for each working solution. Wimberley's WD2D can be seen as the evolution of D-7. Wimberley did away with the B solution, refined the ratio of pyro to metol, increased the bisulfite in the A solution to make up for the sulfite lost by omitting the B solution, and cut the carbonate in half, which allowed him to eliminate the restrainer. WD2D was the first pyro staining developer of its kind, and a true innovation. PMK Pyro's contribution to the evolution of pyro developers was to decrease the pH of the working solution by substituting sodium metaborate for sodium carbonate, thereby reducing the apparent grain. The next breakthrough came from Pat Gainer, who introduced the idea of using TEA as a solvent/base, and thereby permitting the formulation of single solution pyro developers. His own formula, Pyro-TEA, isn't really a formula as much as a proof of concept, and contains only pyro and TEA. As simple as this developer is, it works surprisingly well, and represents an improvement over ABC Pyro in terms of grain, consistency, shelf life, and ease of use. The addition of ascorbic acid improves the developer considerably, and the result is a developer that gives nothing away to ABC Pyro for all its improvements. This developer represents a return to first principles, and can be seen as the evolution of Kodak SD-1. SD-1 represents a developer that makes no compromises for keeping properties. It is the pyro developer in its purest form.

Kodak SD-1 Stain Developer

Water (125° F or 52° C) 500 cc
Sodium sulfite 1.4 g
Pyrogallol 2.8 g
Sodium carbonate 5.3 g

Water to make 1000 cc

Use undiluted.

SD-2 (Solo)

TEA 75ml
ascorbic acid 6.5g
pyro 13g
TEA to 100ml

Dilute 1:50- 1:100

As much as I like the idea of it, it's simplicity and faithfulness to SD-1 as a single agent pyro developer, it just doesn't do anything 510-Pyro doesn't do better. But, if you're a purist and want a single agent pyro developer, SD-2 is an excellent choice.

onnect17

29-Dec-2010, 15:39

Roadblock. TEA's viscosity is too much for a sub 60's basement. Unless I find a substitute for it TEA with a lower viscosity 510-Pyro and Pyrocat Uno have not practical use for me. Pain in the a** to mix it and a pain in the a** to use it.
I can't even imagine photoformulary could market anything like it.

Jay DeFehr

29-Dec-2010, 16:34

To mix TEA-based concentrates:

Add chemicals to 1/2 final volume of TEA at room temp, and stir. Top up to final volume with TEA, and stir again. Heat with stirring until everything dissolves. Simple. If your TEA is too viscous, just heat it a little. 510-Pyro is much simpler to mix and use than a two part developer.

mikebarger

29-Dec-2010, 16:43

Until I get the heat going in the darkroom my 510 is below 60 and I don't have any trouble using a baby medicine syringe to dispense it.

If you can't heat the TEA up to 150 to mix it, you may need to stick to powdered mixes with water.

onnect17

2-Jan-2011, 15:06

Thanks to all for your input regarding how deal with TEA's viscosity. At the end I got a small microwave for the basement and the mixing worked exactly as Jay said. I already used the 510 in several developing tests.
Armando

Jay DeFehr

2-Jan-2011, 17:24

Armando,

I'm glad you found a solution that works for you. Be sure to save some of your 510-Pyro for actual photos, that's where it really shines.;)

photobymike

12-Jan-2011, 21:06

The more i read, the more confused i am getting. I want a developer that i can control the dynamic range with. I want detail in the shadows and the clouds. It seems that Ken Lee and Sandy king have nailed it. I have made the move to Pyrocat HD Glycol. I am going to try it next week on tmax 100. Ken or Sandy ,it might be useful to publish a web glossy page on standard terms used in the discussions here. Something to refer to when there is confusion. I think alot of people are mistaking contrast with dynamic range. Suggested times and temps for different films would also be helpful. Its here, but scattered thru the discussions. In 40 years i have tried just about every kind of developer formula on my film. The magic bullet would be to control that dynamic range and contrast with a developer. LOL a Zone System Developer with different formula to control dynamic range...WOW...with one developer.... To be able to make different negatives for the scanner, wet darkroom, and alt process.

Which Pyro? look at the pictures of Ken Lee and Sandy King.
keep it up i am reading with much interest...

Jay DeFehr

12-Jan-2011, 21:24

Mike,

Perhaps you could define dynamic range for us? Do you mean density range? I think dynamic rage is a digital term. Or, perhaps you mean Subject Brightness Range, as in the range of illuminance in the scene that can be represented on film? I'm not sure what you mean by, "I want a developer that i can control the dynamic range with". If you mean a developer suitable for expansion and contraction development, I think any developer can do so, to varying degrees. If you want a developer to represent very long illuminance ranges, there are special developers formulated for just such needs, like the famous POTA phenidone developer, or you can adjust other developers, like Pyrocat, Hypercat, 510-Pyro, etc., to do the trick. Same goes for expansion development. Any of these developers can be used to make negatives for multiple printing processes.

onnect17

12-Jan-2011, 22:54

Mike,
There are too many non-linear functions in the middle to obtain a linear response in the negative. Pyro developers add the stain to the equation. Even if you end up with normal grain in the low density areas to almost all the grain masked in the high density parts of the negative (good thing for scanning) still is not a straight line.
In the meantime, here's a TMX 35mm shot developed in 510-Pyro. No curves in PS, just gamma, to get the light as real as possible.
Armando

Ken Lee

13-Jan-2011, 08:17

I want a developer that i can control the dynamic range with. I want detail in the shadows and the clouds.

If you want to accommodate scenes of much much greater than typical range, then special measures are required. People who use "Beyond the Zone System" call these scenes of high subject brightness range, or SBR. They are what digital people call scenes of high dynamic range or HDR.

They are what we all call... a challenge. :)

For that, using a divided developer is one approach. Divided Pyrocat is one of those divided developers. Diafine is another. There are more formulas.

There are also diluted developers, water-bath developers, two-bath developers... etc. You can read about them in Ansel Adams' book "The Negative". You can find formulas in Anchell's book(s). They have been discussed on this forum quite a bit too.

Another approach is to make multiple negatives/positives and merge them digitally. This is similar to what digital people call HDR.

Another approach is to scan a single negative at different scanner settings, and merge them. Your mileage may vary, as they say.

In my experience, the easiest method is divided developers like Divided Pyrocat and Diafine. The only issue is that all negatives are developed to a very similar range of contrast. You usually have to add contrast when printing.

Not all scenes will look good when highly compressed. That's subjective.

sanking

13-Jan-2011, 08:59

Just for the record the term dynamic range was in use in photography a long time before digital photography. It has several meanings but more commonly it refers to the range of subject brightness (or luminance range) that can be captured by film or by a digital sensor. Some film, transparency for example, has a very limited dynamic range of only five or six stops, but many B&W films have a very long dynamic range, twenty stops or more if combined with the right developer and method of development.

The term HDR (or high dynamic range) is of more recent origin and has its origin in digital. It could also be used with film but that use is very rare.

There are several methods of developing film that was exposed in scenes of very high SBR but the best method by far, in my opinion, is the use of a divided developer, especially if you develop film to scan. Normally divided development gives a negative that is almost perfectly linear in its disposition of tonal values, and then in PS you can control contrast by the use of curves or other local adjustments.

I have used Diafine and divided Pyrocat-HD for two bath development. Other formulas may work but because this method of development requires some very specific procedures not commonly used in film development test carefully first before risking valuable negatives.

Sandy

Drew Wiley

13-Jan-2011, 10:13

Mike - I'm not sure how much range you've got in mind. I've used TMax 100 in extremely bright direct sun snow scenes in the mtns are have gotten detail in the print
all the way from deep shadows right up into the highest sparkly highlights using just
regular pyro tray development (not conventional developers). But TMX is more finicky
in exposure than many films - you definitely don't want to overexpose it or you'll send
the curve up onto the shoulder and blow out the highlights. TMX can handle long
illluminance range but is certainly not my favorite for this kind of work. ACROS is much
more forgiving provided you give enough exposure to push the shadows up the curve
(I rate it at 50). And a film like Efke 25 will give you plenty of range to work with, but
is slow and a bit fragile to handle. With 8x10 I'd reach for TMY (400) or probably choose it even for 4x5 unless you want really huge enlargements; it's a lot more forgiving than TMX. Don't get me wrong - TMX100 is a very versatile film capable of
handling difficult situations, but just has a fussier learning curve than some other films.

photobymike

13-Jan-2011, 13:07

Thanks very much for the information and lively discussion. Thanks Sandy for clarifying what i mean.:-) Detail detail... in the shadows and in the sky. My work flow is analog to digital ... scan to print. Prints that have good detail have the ability to draw you into them, and engage your imagination. Ken's puppy picture is just a fantastic picture to look at. The puppy detail makes you want to explore the rest of the picture. Maybe its a Gestalt thing, i don't know. HDR or high definition prints sometimes have to much.. mmm well they look doctored, or digital... more of a feeling when you look at a HDR print. What i try and do is match what the brain expects there to be detail.. A print with a natural looking toe and some clouds is what i try and print. I can do a lot with a my scanner, but i cant put detail in the shadows if it is not there to begin with.

Same negative scan light and dark mmm interesting idea.

I just ordered some Efke film. I am going to develop in a Jobo tank with a slow roll. I have modified a Beseler drum roller so i can vary the speed. I am going to try different dilutions of the B solution as well as temp variable. LOL i like the Photo Flo discussion.. not so sure i want to contaminate multi hundred dollar tank.

onnect17

22-Jan-2011, 16:56

FWIW, After testing 510-pyro and Pyrocat-HD with TMX the results I got are very similar and both far better than xtol.

photobymike

24-Jan-2011, 06:30

OK a follow up on my experience with PYROCAT HD GLYCOL .
My first impression was oh crap thin negatives. Oh well i will try and scan them anyway. WOW not thin at all just right.... They have a very good shadow detail (i exposed for the shadow) and i could see the paint defects on my white Toyota!!! SHAZAM highlights... I really like these chocolate negatives. They seem to match what my scanner expects (v750 epson). I do not have a densitometer, but the negs seem more linear with not much of a toe. Well anyway they scan very well; better than any other negatives i have. Thanks again guys

Ken Lee

24-Jan-2011, 09:12

As a rule of thumb, we can always add contrast while scanning, or after scanning. If your negatives are thin, then as long as they aren't underexposed in the shadows, you can get a good image out of them.

That being said, I usually aim for a negative whose density occupies around 70% of the histogram. (When shooting scenes of normal subject brightness range). This leaves a comfort factor of around 15% at each end of the scale, in case we want to add contrast.

It also allows us to change scanners in the future, and not automatically exceed the dynamic capacity of the new scanner, if it is less than that of the current scanner.

Most importantly, this approach adjusts the dynamic range primarily via exposure and development - which are analog processes, where the contours of brightness are curves, rather than discrete steps.

Roger Cole

25-Jan-2011, 16:47

Thanks. "get over it," and "get used to them" seem to be the operative phrases. So be it.

On the subject of gloves a few pages back, how about just keeping your hands out of the stuff? I've never used gloves for developing or printing. Mixing, yes, actually working, no. But then again I always used tongs for printing and developed film in daylight tanks (35mm and roll) later deep tanks for 4x5 and then later still a Jobo, none of which involve sticking my hands in the soup. I can see that for tray development of sheet film where the total darkness (or even very dim green inspection safelight part way through) would make tongs pretty much impractical, and possibly damage film emulsion as well.

But are folks suggesting gloves just in case of splashes and the like when the hands are not actually intentionally immersed?

Back to the general subject of developers, I've never used a staining developer but once I get my darkroom set up again might experiment. I have used Diafine, quite a lot of it for 35mm going back to my days in 80-81 on my high school yearbook staff, and always liked it for 35mm. Then I was using it for a very effective push of Tri-X but I've often thought about it for taming high SBR scenes on sheet film. How are people using it for sheet film? Trays? Deep tanks? Either seems workable. I do recall it seemed quite sensitive to over agitation and I got best results strictly following the instructions of inverting the tank once only, gently, each minute.

Drew Wiley

25-Jan-2011, 17:12

mikebarger

25-Jan-2011, 17:20

Just as easy could have been Jack and smoking that cased the health issues, could have been polluted well water, how about any number of other chemicals?

A fair amount of speculation without many/any facts.

Drew Wiley

25-Jan-2011, 17:28

Mike - it's pretty well known that pyro is toxic, and like chromium salts or mercury vapor, one of the bad guys in photograhic history if used carelessly. How all these kinds of things interact doesn't cancel out their effect, but might ADD up in ways
difficult to predict. Upriver from here they get their drinking water from central Calif
rivers where trace amounts of pesticides get in the supply; then they get noxious fumes from local refineries. But here on the coast we get water from Sierra snowmelt,
and the refinery crud generally gets blown upriver. it would be difficult to predict the
result of any specific segment of this, though the EPA has threshold guidelines, but
the cumulative effect is that, right up there river there is twelve times the cancer
rate as in our neighborhood. We call it "Cancer Alley'. If someone wants to be macho,
then smoke and dip your hands in pryo too; slow death, either way.

mikebarger

25-Jan-2011, 17:31

You missed the Jack and smokes :)

Drew, no offense intended. I worked some amount of years in safety in a manufacturing environment. I had a personal peeve when someone would state this is toxic to the hourly employees without providing information as to what exposure is toxic, or giving some real world examples of what a toxic amount looks like, or how many years it might take to really put you in some kind of danger.

If you drink enough water a one sitting it can be toxic to your system.

I'd just like to see some real life examples of what is a toxic amount of diluted pyro is, is it one splash, 4,000 hours of exposure?
I know I don't know the answer.

Gem Singer

25-Jan-2011, 17:51

Drew,

Most folks who tray develop their film in Pyro are wise enough to wear protective gloves.

There are no noxious fumes to inhale.

They are also knowledgeable enough not to drink the stuff.

onnect17

25-Jan-2011, 19:06

Drew,
You should be careful not only with pyro but with a lot of other toxic and short term death guaranteed products like "organic spinach".
http://en.wikipedia.org/wiki/2006_North_American_E._coli_outbreak

Roger Cole

25-Jan-2011, 19:10

Roger - pyro developers are toxic, and if you can keep casual splashes off your skin
without gloves you are a lot more coordinated than me! I do tray development with
large format, so they are a must; but even with small format tank development I
consider nitrile or rubber gloves a must. For one thing, they rinse off well so I don't
get one chemical step contaminating another. For another thing, we don't really know
just how much exposure to something like pyro is too much. It was probably the factor
behind the Parkinson's disease of Edward Weston and several other old-time photographers. Artists tend to be nonchalant about their work risks, and I know so
many of them who are now my age and very sick due to some kind of accumulated chemical exposure over the years. Not worth it, especially given the extemely low cost of gloves.

Drew,

Most folks who tray develop their film in Pyro are wise enough to wear protective gloves.

There are no noxious fumes to inhale.

They are also knowledgeable enough not to drink the stuff.

Tray developing with pyro, no question. I wasn't questioning that. But I bet Weston stuck his hands directly in it doing just this, not a small splash now and then.

I was more asking if people actually used them for things like the usual MQ or (less likely to cause problems) PQ developers when tank or rotary processing.

I will certainly use them if I tray develop sheet film, and I will certainly strongly consider using them if I ever give pyro a try. I'm not sold on using them for tank/rotary development of film using the more common developers, or tray developing prints using tongs, assuming the usual print developers and not amidol, for which I'd be prone to cover hands and everything else I could just to avoid stains, never mind toxicity. Note that "not sold" != "dead set against." I'm willing to be convinced, but it would take more than the suggestion that an abundance of caution is wise. I think driving to work is probably a lot more dangerous, but we all have to asses risk for ourselves and do what we think is appropriate.

mikebarger

25-Jan-2011, 19:48

Well spoken Roger

Drew Wiley

25-Jan-2011, 21:53

Suit yourselves. Pyrogallol has had industrial uses for centuries and there's plenty of
medical evidence on it. And it will vaporize at a certain point in hot water and can
lead to inhalation poisioning. It readily penetrates skin. Yes, EW put his hands right in it. But what is very difficult to predict is the superadditive effect of all the different environmental contaminants we become exposed to. I use pyro at least once a week, sometimes more often. But fume control, moderate water temperature, and nitrile gloves are just common sense. Not every photographer or
artist has common sense, unfortunately; and I know quite a few with lead poisioning, dioxion poisoning, chromium poisioning, lacquer nerve destruction, and
all kinds of esoteric cancers. Are any of our creative endeavors worth ruining our
health over?

Roger Cole

25-Jan-2011, 21:57

Not much argument there, but what does that have to do with tank development with MQ/PQ developers?

Drew Wiley

25-Jan-2011, 22:04

Roger - more specifically to your point ... hypersensitivity or allergy to an otherwise
mild chemical is something which can happen suddently. We all know about things like metol, or out in the woods, poision oak (well, we should know). Over the years
I have personally become sensitized to glycols and certain ingredients in RA4. That's
why I mix and drum process RA4 outdoors. I know people who worked in epoxy plants for twenty or more years without an apparent problem, then all of a sudden
broke out into hives, and now can't even touch a desk with a baked-on epoxy finish
twenty year old. Three owners of former big photolabs in this area have experienced
severe health problems from overexposure to color chemicals. In each case it was
a career game-changer. That's why things like MSDS sheets exist in the first place.
Most of our common black and white darkroom chemicals are relatively innocuous.
But I won't handle any of them without gloves. Sodium sulfite is used in wines and
on fast-food salads, but my sister is deadly allergic to it and has to select wines
free of preservative.

Roger Cole

25-Jan-2011, 22:55

Those are good points, Drew. I seemed to develop a sensitivity to almonds (thankfully not bad, just mild nausea and I sometimes accidentally eat something containing them without reaction) after years of happily munching away on them.

When I used to print RA4 (90s) I used the Tetanal room temperature stuff and the fumes nearly drove me out of the (fairly ventilated at that) darkroom. I do have exercise induced asthma and had childhood asthma. It called for double BW strength stop bath. It never bothered me in BW but boy - something in that RA4 developer hitting that double strength acetic was horrid. I changed to an odorless citric acid based stop and it completely stopped (pun intended) the problem.

Oh yes, and I used to get headaches if I ate at a certain salad bar that used way too much sulfite. I started pre-treating with a tylenol before dinner on the rare occasions I went there. I never had a problem with it in the darkroom, but then again I grant that's "not yet."

Getting back into darkroom work now in my late 40s after a layoff of more than 10 years and I'm certain I'll be more careful than I was in my 30s.

photobymike

25-Jan-2011, 23:00

I give Pyrocat plenty of respect, i dont use gloves but am very careful.

Reminds me of the old timer that taught how to print many many years ago. He used to taste the fixer to see if it was any good. Well one day he just turned gray, really really gray. weird i know but the doctors said his body had accumulated silver in system that was photosensitive. and well he got exposed LOL LOL.... true story....

Roger Cole

25-Jan-2011, 23:04

Jay DeFehr

26-Jan-2011, 21:47

Lots of things are dangerous, the question is, how dangerous? In all these discussions about the toxicity of pyro I've never seen anyone post the LEL for it. I wonder, Drew, do you wear gloves when you pump your gas? I'd be willing to bet the gas you pump and the fumes coming from it are far more dangerous, by orders of magnitude, than the very dilute pyro developers we use. Attributing Weston's illness to his exposure to pyro is not only alarmist, it's completely unsupportable. When you say "probably", you suggest there is some calculable probability, but for that to be even possible, there would need to be some documented link between pyro and Parkinson's disease, which there isn't. It would be far more accurate to say his Parkinson's was definitely not caused by his exposure to pyro, because there is simply no medical evidence to suggest it's possible. Catechol, by the way, is used as a topical antiseptic in much higher concentrations than any film developer.

Merg Ross

26-Jan-2011, 23:32

Attributing Weston's illness to his exposure to pyro is completely unsupportable.

Are you certain of this?

Drew Wiley

26-Jan-2011, 23:39

Jay, maybe you should do a little homework before you go spouting.

Ken Lee

27-Jan-2011, 02:58

If one is soaking one's hands in photo chemicals every day for hours on end, then sure, gloves are important. Few of us do that, unless we work in a lab as a full-time profession.

I wouldn't soak my hands in sea water for hours on end, and not expect some kind of adverse reaction. You certainly don't want too drink much, or you'll get a nasty reaction.

I agree with what Jay has said. It doesn't hurt that he's a Chemical Engineer of course, but common sense tells us that many household cleaning products are just as dangerous, if not more dangerous, than diluted pyro developer in a tray. Their packaging often warns us to contact our nearest poison control center if we ingest them.

If we were to swallow some household bleach or ammonia, or even inhale too much of it, we'd be in a real... pickle as they say. Never mind gasoline or paint thinner - or even most paint for that matter. Even table salt, NaCl, can be very dangerous when consumed in excess.

IanG

27-Jan-2011, 03:37

I agree with what Jay has said. It doesn't hurt that he's a Chemical Engineer of course, but common sense tells us that many household cleaning products are just as dangerous, if not more dangerous, than diluted pyro developer in a tray. Their packaging often warns us to contact our nearest poison control center if we ingest them.

Don't under-estimate the toxicity of Pyrogallol and Pyrocatechin, sure there's plenty of dangerous household chemicals but they aren't absorbed into the body in the same way (through the skin) as these organic developing agents.

Gloves are cheap, so it makes sense to be cautious.

Ian

mikebarger

27-Jan-2011, 04:02

Cautious, but not alarmist. I've known many people with Parkinson's that never stepped a foot into a darkroom.

Jay DeFehr

27-Jan-2011, 08:28

Drew,

You're right, I didn't do my homework. I've been searching for any credible link that states pyrogallol causes Parkinson's disease, and I can't find one. Can you provide a source that says pyrogallol causes Parkinson's? I'd be very interested to know this. What I was able to find fairly easily, is that both catechol and pyrogallol are used as topical medications in higher concentrations than we would ever use in developers. I think that's significant. What separates medicine from poison is often the dosage, so without specifying the Lower Exposure Limit for a chemical, we can't say with any authority whether a chemical is one or the other.

Jay DeFehr

27-Jan-2011, 08:31

Ken,

I'm not a chemical engineer, or any other kind of engineer, for that matter. I don't know much about chemistry. Sorry to disappoint.

Mark Sampson

27-Jan-2011, 09:44

Any evidence that Edward Weston's use of pyro developers caused his Parkinson's disease (or any other health problem) is anecdotal at best. The research hasn't been done to prove or disprove that claim. That said, anyone with concerns about their long-term health should not be putting their hands in developers- pyro or otherwise. By far the best-known and best-documented health hazard from developers is contact dermatitis, caused by sensitization to metol, a common ingredient in many film and paper developers. I first contracted dermatitis in 1985- luckily a mild case easily treated. Since then I've worn gloves when using developers and it's never come back (yet). I avoid developers with a high concentration of metol, for example Ansco 120 and Kodak Selectol-Soft. I also develop film in trays with PMK- but taking extra care when developing film is always a good idea.

bob carnie

27-Jan-2011, 10:05

From a very practical point of view .

Sometimes I am printing silver prints over many days, at times 14 days straight, I can tell you despite the exhaustion, near the end of a really long stretch I start feeling nauseated around the fix specifically, I have a monster venting system but even then with huge open trays I feel like there is this buildup of crap in my system and I have to go north to fresh air or just get out of the darkroom for a period to get back to normal.

For years I did not wear gloves , and I did start getting rashes and such on my hands and arms, switched to gloves and ever since I do not get the rashes on my hands or arms.

Occasional use in the darkroom , and I am just fine , but during peak printing times I have noticed this buildup.

Merg Ross

27-Jan-2011, 10:06

Any evidence that Edward Weston's use of pyro developers caused his Parkinson's disease (or any other health problem) is anecdotal at best. The research hasn't been done to prove or disprove that claim.

That is my understanding. However, extensive research suggests that exposure to toxins increases the risk of Parkinson's disease. Unfortunately, the half-dozen photographers that I know, or knew, with Parkinson's disease were unaware of the risks.

Since this thread has strayed from the original question into the area of safety, let me offer that Amidol is a known carcinogen; also something of which earlier photographers were unaware.

Drew Wiley

27-Jan-2011, 10:19

I really don't have a bone to pick. I'm tired sick of seeing so many of my art and craft
friends destroying their health in one way or another. Some shake incessantly, a couple of them are blind, some have rare cancers, and quite a few are dead from strange causes. And in a University and mfg neighborhood like this one, we've got a saying, that there are three kinds of people who don't live past 52: cropdusters, industrial painters, and research chemists (they all get just too comfortable handling hazardous products). Never mind dopers, glue sniffers, and alcoholics. The EW rumor
has been around for a long time, but it has a basis. Several pyrogallol abusers got
Parkinsons, so it didn't seem like a coincidence. When a drop of it hits the skin, many
have reported an instant rubbery taste (even if the drop hit your arm); I have experienced this. This tells you that not only does pyro instantly penetrate the skin, but that it has a particular affinity for nerve synapses. Beyond that, there is plenty of medical data on file to reinforce such suspicions, even if it is impossible to know if this is the exact source of EW's personal disease. As far as the nonsense about certain chemicals being safe because they're used in medicine, things like digitalis, warfarin, and botulinum toxin are also routinely used in medicine, but are incredibly dangerous casually. Allergic sensitization is a somewhat different topic. But I also consider gloves
a good idea because many chemical stick to skin much better than gloves, and a simple rinse avoids the risk of cross-contamination of working solutions. So no, my
fingernails are not stained from amidol, but I have one pair nitrile gloves which certainly
is!

sanking

27-Jan-2011, 10:52

I am with Drew on this. Although there may not be any specific study that links Parkinsons disease to pyro it still makes sense to protect ourselves in every way possible from toxins, and both pyrogallol and pyrocatechol and many other reducing agents are toxins. I became sensitized to two part epoxies in the 1980s from building a laminated sailboat and since that time I have been very conscious of protecting my hands from all chemicals. And I insist that students who do workshops with me do so also. For example, when I teach carbon transfer workshops some of the students do not want to wear gloves when carrying out certain of the operations that involve dichromate because their thinking is that the dichromate is so diluted at this point that it will not cause any harm. But I know from experience that an accumulated effect of even highly diluted dichromate can eventually cause severe dermatological problems, even if it does no more harm than this. I also work this way with pyro developers and always protect my hands with gloves even when doing processing in tubes or drums where there should in theory be very little opportunity for the pyro to contact my hands.

Bottom line on this for me is that if you are not protecting your hands with gloves from all darkroom chemicals you are making a mistake that could potentially cause you a lot of problems down the line.

Sandy

onnect17

27-Jan-2011, 13:03

I buy the boxes of disposable gloves in Costco or Home Depot and use them new in each session (except for loading the film). If I need to mix any dry chemicals I do it outside the house, wearing mask and gloves.
Now, regarding other "stuff" in the air in the water, the pollution is incredible here in the Boston area, specially in the train terminals.
This is not my opinion, I can prove it.

Jay DeFehr

27-Jan-2011, 13:17

We deal with lots of toxins every day, and most people don't wear gloves when they do. Just about every household chemical is toxic at some exposure level, but who wears gloves or respirators when they pump their gas, or spray anything from WD40 to bug spray, brew coffee or tea, add bleach to the laundry, etc., etc. "Protecting ourselves in every way possible from toxins" is a hurculean task that would have us all in Tyvek suits and breathing supplied air at all times, because we are surrounded by and inundated with toxins everywhere we go. We all decide to expose ourselves to toxins every time we eat or breath or touch something without protection. The fact that toxins can also be antitoxins, and medicines poisons should indicate the importance of context in these kinds of discussions. That pyrogallo and catechol are both used specifically as topical medications, the exact same route of exposure as a darkroom exposure, should not be trivialized, and the comparison to botox, etc., is a very disingenuous one. The medical uses of catechol and pyrogallol are not he kind in which very toxic side effects are tolerated for the greater good, as in the case of chemotherapy, etc., but for treating relatively non-threatening conditions, for which a risk of Parkinson's disease would not be acceptable. I think it's important to know what the actual risks are, and then to apply common sense.

onnect17

27-Jan-2011, 13:30

IanG

27-Jan-2011, 13:54

There's a huge difference in using controlled does of Pyrogallol for serious medical conditions and uncontrolled absorption through the skin which amy build up over time.

A small number of photographic chemicals are far more hazardous by skin absorption than any household chemicals which are always used with gloves.

Some like Dichromate, which Sandy mentioned, if they get into a small abrasion or cut will cause ulceration which won't heal, so will need medical treatment, that's from first hand experience.

Others like Pyrocatechin & Pyrogallol as well as Amidol can cause long term medical problems with some people, maybe only a few but there were know medical issues around darkroom working prior to WWII with people spending long hours processing. These disappeared with the switch to cut film, greater use of daylight developing and also mechanised photofinishing (film & paper processing). At same time developers like Pyrogallol & Pyrocatechin almost fell into disuse except for a few proponents.

One consequence was by the end of WWII most darkroom chemistry was less toxic by skin absorption and medical reports had stopped. There are scientific articles on the medical hazards of darkroom chemistry and they aren't taht hard to find either.

Ian

Drew Wiley

27-Jan-2011, 14:14

Certain things which were common household and labor products just a decade or few decades ago are now banned from mfg outright because they proved so hazardous.
Look up some of the things in ladies' nail polish, and the ingredients are banned from
current used in industrial paints they're so hazardous! Talked to just one ambulance
dude that had to resucciate eight nail parlor customers in just one year. Look up the
statistics of how many women died from hair spray aerosols in the 50's and 60's.
Twenty years ago I had my employer chewing me out for warning people to wear
rubber gloves when handling doors treated with pentachlorophenol. Every single person
who worked in that door plant died prematurely from cancer. No different today. Back
then folks were screaming about the Fed damaging business by enforcing asbestos
regulation. I know a few folks who died from asbestosis from just casual exposure.
No, I'm not a hypochondriac. But I know the difference between acetone and lacquer
thinner, for example. Acetone is flammable and will dry out and irritate the skin. Lacquer thinner will go right through the skin into the bloodstream and can cause severe health problems. I've known folks who worked with it intensively for only six
months and were crippled and unemployable for life. But for some reason artist's think
its cool to be macho with stuff. Blend your oil and cadmium pigments with your fingers
for example, because gloves are a nuisance, then get palsy ten years later.

Roger Cole

27-Jan-2011, 14:40

I don't hear anyone saying to blend oil and cadmium pigments with your fingers. I do hear people questioning wearing gloves for doing things like rotary and tank processing, even with pyro. In my case, I wasn't even questioning that very much, but rather those who indicated gloves for just the usual MQ or PQ developers, acetic acid and fixer, in rotary or tank processing or printing with tongs.

There are degrees of risk, and unfortunately it isn't always possible to accurately asses them, so we have to work with the info we have. It seems there's enough evidence that pyrogallol and pyrocatechin are more dangerous than most other developing agents (metol, phenidone, ascorbic acid etc.) that metol is much more like to cause contact dermatitis than phenidone etc. Oh, and fixer, particularly used fixer containing silver, shouldn't be ingested. :rolleyes:

Some are only going to feel comfortable wearing gloves for all darkroom work, and that's ok. As I said, I use them for mixing chemicals and would seriously consider using them, probably would, if I were using pyro, but I haven't so far used them for rotary and tank processing with MQ or PQ developers, nor for printing with tongs. (I did use them for Ilfochrome then called Cibachrome, back in the late 70s when I noticed that spilling a drop of the bleach on a concrete floor sizzled! To be fair that risk was probably "just" that of a chemical burn - unpleasant but not long term deadly, but it persuaded me to use gloves for that stuff.)

Drew Wiley

27-Jan-2011, 14:54

Roger - that fizz from Ciba bleach wasn't innocuous. The main ingredient was conc
sulfuric acid! It can easily burn your skin and destroy your lungs if inhaled. Another
reason to read the warning sheets before mixing this or that. Have a friend who once
ran a big Ciba lab with over 200 hundered gals of bleach in replenishment tank. Cost
his several hundred thousand dollars to repair the plumbing before he could sell the
bldg, and he had ten years of medical work including repeated surgeries to remove
scar tissue before his lungs were halfway back to normal. Another lab owner couldn't
even enter his own place of business due to sensitization. The hazmat and zoning issues alone were a major headache. Fortunately, for us small volume one-shot drum
users of Ciba, all we've got to do is drain the bleach into a plastic bucket with a little
baking soda at the bottom, and it's instantly neutralized. Plus good fume extraction or
ventilation (I run the drum on a cart outdoors). I would never, ever let color chemcials
touch my skin, although Ciba fixer isn't much different from non-hardening ordinary
b&w fixers. The stop bath I use for RA4 doesn't any higher concentration of acetic acid than the vinegar used for salad dressing. But since I dilute it from glacial acetic acid, I better know the difference!

Jay DeFehr

27-Jan-2011, 14:54

Ian,

That's just my point, catechol and pyrogallol are used for relatively non-serious medical treatments, and used topically, ie applied directly to the skin, in much higher concentrations than those used in developers. Misrepresenting the risks does nothing to enlighten darkroom workers.

Pyrogallol as a treatment for lung cancer:

http://www.ncbi.nlm.nih.gov/pubmed/19233505

Lifetime dermal exposure of mice and rabbits to low doses of pyrogallol did not induce
toxic effects.

http://www.qualityhealth.com/health-encyclopedia/drug-information/pyrogallol-skin

http://www.deepdyve.com/lp/sage/final-report-on-the-safety-assessment-of-pyrogallol-4Kd0SeaG1q

http://cat.inist.fr/?aModele=afficheN&cpsidt=20544959

There seems to be some evidence that pyrogallol is useful in many different forms of medical treatment, and is safe to use in cosmetics. I don't drink pyrogallol, or inject it, or even soak in it, and I don't panic when I get a few drops of a weak solution on my hands. I do wash my hands after a processing session. Maybe I'm being terribly reckless, but no one in the medical field seems to think so.

Jay DeFehr

27-Jan-2011, 14:58

Drew,

I'm beginning to be grateful we're not personally acquainted; it seems everyone you've ever known has fallen to some form of chemical exposure.

Drew Wiley

27-Jan-2011, 15:06

Jay - you're referencing do-it-yourself snakeoil sites, not medical literature. You can find sites like that that tell you how to smoke vanadium. You are not doing anyone a favor by pooh-poohing known chemical hazards. Yeah, I once had a kid working here
with a liver deficiency, who would end up in the emergency ward if he ate a Big Mac
due to the preservatives in it. Most people are more likely to die from eating too many
Big Macs and resultant obesity. Drinking a Coke would kill him. I once sat on a plane next to a Coca Cola exec. My wife asked her if she got her soda free. She said she wouldn't drink the stuff herself because all the ingredients were shipped hazmat. Well I'm not afraid of a soda now and then, but wouldn't want the original conc carbonic acid to even touch my skin. My wife has had several patients just the last few weeks
who tried to bootleg a cure for this and that and now are in very real trouble, facing
major remedial action.

Drew Wiley

27-Jan-2011, 15:19

Just saw your last post jay. My experience and personal contacts are not coincidental.
At one time everything within walking distance of my office was ringed by industrial
mfg sites, including paint factories. Now all of them have been kicked out of town due
to environmental concerns, and pharmaceutical companies and breweries have taken
over, and a lot of restaurant and studios. I know a lot of artists working in many kinds
of media - was talking to a remarkable one half hour ago, trying to help him with a
fabrication issue. When I was younger, I could have gone into public health and then
onto the EPA. Glad I didn't - my friends there exploded with estoteric multiple cancers
from merely monitoring illegal pesticide use in this state; dead illegal farm workers were
sometimes found in the fields (touching a single drop of Parathion is fatal). I routinely
talk to university and rescue medics, and of course, have had several family members
involved in specialized medicine, including my own wife, who works in reconstructive
plastic surgery and encounters many strange forms of cancer. The lead surgeon goes
to Vietnam to operate on some of the hundreds of thousands of children with birth
defects from agent orange. The oldest employee in my company invented agent orange
as an agricultural herbicide and has had all kinds of strange medical issues and treatments, but is thankfully still alive. Yeah, you can poo-poo that these kinds of
problems could have been caused by drinking orange juice, but for some reason dioxins
are now completely banned from mfg in the US and most other countries. Coincidence?

Roger Cole

27-Jan-2011, 15:21

Drew - I didn't mean to imply that Ciba bleach was innocuous, only that spilling a bit on your skin from occasional use might burn you, but probably wouldn't give you cancer or Parkinson's or whatever. And I never inhaled much of it, as you say. I also didn't have 200 gallons, and I used the neutralizer or baking soda per instructions.

The fixer pretty much was BW rapid fixer, or close enough that some of us just starting buying the bleach. You could use BW print developer and fixer just fine, but you needed that narsty bleach.

As I mentioned before, normal RA4 stop bath isn't any higher concentration. For the Tetanal room temperature RA 4 I used to use, they recommended double BW strength. It nearly choked me out of the darkroom, but it seemed to be something released when the developer was carried over (stronger developer for room temperature, I'd think - I've heard you can simply use RA4 replinisher for this.) I changed to a citric acid stop and for whatever reason, that fixed the problem. At least it didn't smell nearly as bad and I didn't get a sore throat anymore. I can't say for sure that nothing toxic was released, of course.

IanG

27-Jan-2011, 15:34

Nothing I said agreed with your point, just the opposite.

There's plenty of scientific & medical evidence that professional darkroom workers prior to WWII suffered from an numbers of ailments & complaints as well as then unexplainable sicknesses.

As I pointed out earlier that changed post WWII with a switch away from chemistry using Pyrogallol, Pyrocatechin and Amidol because smaller formats needed finer grain developers and could be mechanically processed.

You van use out of context web pages to claim these substances are safe thats not the medical and scientific view even today.

Ian

Ian,

That's just my point, catechol and pyrogallol are used for relatively non-serious medical treatments, and used topically, ie applied directly to the skin, in much higher concentrations than those used in developers. Misrepresenting the risks does nothing to enlighten darkroom workers.

Pyrogallol as a treatment for lung cancer:

http://www.ncbi.nlm.nih.gov/pubmed/19233505

http://www.qualityhealth.com/health-encyclopedia/drug-information/pyrogallol-skin

http://www.deepdyve.com/lp/sage/final-report-on-the-safety-assessment-of-pyrogallol-4Kd0SeaG1q

http://cat.inist.fr/?aModele=afficheN&cpsidt=20544959

There seems to be some evidence that pyrogallol is useful in many different forms of medical treatment, and is safe to use in cosmetics. I don't drink pyrogallol, or inject it, or even soak in it, and I don't panic when I get a few drops of a weak solution on my hands. I do wash my hands after a processing session. Maybe I'm being terribly reckless, but no one in the medical field seems to think so.

Drew Wiley

27-Jan-2011, 16:23

Roger - I really don't know what the thing is with RA4. It's probably some minor ingredient. I have my suspicions. Lab owners sometimes got sick. I can work with
RA4 for about two weeks with no problem, then wham, I get sensitive, get a sore
throat, and catch a cold or whatever respiratory thing is going around. Even an organic vapor respirator doesn't help, so it must be a sensitization issue in very small dosages. Ciba is much easier to control because it's mainly a simple acid issue. I ration my printmaking very careful and do the actual chemical processing outdoors. My 30x40drum processor is rigged up on wheels. I have a nice level concrete pad for it, and the wind direction is predictable. I'd like to install a 40" Kreonite roller-transport processor for RA4, but it would be in a special outbuilding with a ventilation system completely separate from my main lab. The only color process I'll do in my black-and-white darkroom is dye transfer printing. Of course, most folks these days solve this whole
kind of problem by printing color via inkjet.

Jay DeFehr

27-Jan-2011, 16:50

Drew,

You seem quite happy to provide nothing more than anecdotes, but the research on pyrogallol for treatment of lung and other cancers is current and credible. I don't think the Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan is a snake oil site. Pyrogallol is currently used as a treatment for eczema and psoriasis, and approved by the FDA. Not snake oil. The International Journal of Toxicology from the American College of Toxicology is surely medical literature, as is the International Journal of Molecular Medicine. Did you even open the links?

Ian,

I know you disagreed. You wrote:

There's a huge difference in using controlled does of Pyrogallol for serious medical conditions and uncontrolled absorption through the skin which amy build up over time.

But my point was that pyro is used for relatively non-threatening conditions like eczema and psoriasis, as a topical medication, to be absorbed through the skin, and I quoted a study that found no toxic effect from dermal contact with pyrogallol over a lifetime in rats. This is current research, and the web pages are very much in context if we're discussing the toxicity of pyrogallol. The FDA has found pyrogallol safe for use in cosmetics. That's the current medical view. No one is saying pyrogallol is harmless, just that its toxicity is limited, and there doesn't seem to be any credible evidence that its use in the darkroom represents a special hazard. "I know a guy who tasted rubber when he spilled a drop of pyro on his arm" is not credible evidence. Your example of pre vs post WWII darkrooms confuses correlation with causation, and is evidence of exactly nothing, supported by exactly nothing.

Drew Wiley

27-Jan-2011, 16:57

"Eye of newt, toe of frog, wool of bat, tongue of dog..." Jay, I think you're one of those guys who loves to play devil's advocate, and that's fine, but I think you'd start
an argument with someone who says the earth revolves around the sun. And I'm sure
glad you don't work behind the counter at a local pharmacy. Read my lips ... right now
I'm in less than 5-min walking distance from major pharmacetical and cosmetics plants.
I talk to their lab techs and even owners frequently. You can't just throw a shovelful
of this or that into anything you want, and there are often extremely involved pathways for how a particular ingredient must be encapsulated. With wife has three
advanced degrees in this kind of stuff. Meanwhile, have fun with your lead-lined
moonshine still.

Jay DeFehr

27-Jan-2011, 17:17

Drew,

I don't know what anything you wrote has to do with anything I wrote, but be well, and for god's sake, don't touch anything!

Drew Wiley

27-Jan-2011, 17:29

Of course you don't understand my comment, Jay, because you're just blowing BS and
obviously don't have much knowledge about this topic at all. You might be a fine photographer with a lot to offer, but you know the saying, if there's smoke, there's fire, and this one certainly smells like a fire made with buffalo chips. I don't have a lot
of formal education on this - just three years each of organic chem and physiology,
and have forgotten 99% of that - but since my spouse has so much ongoing study which has life and death consequences for her patients, I am frequently asked to help
out in the evenings and sort through the websites on a particular topic. The web is
a very very democratic medium. But my "helper" job is to locate the 5% of the sites
with medical info of actual value, so she can home in on those without wading through
the other relatively worthless 95%. Last month she had to deal with the consequences
of a bootleg botox mfg who was only off in the formulation by about .000000001%.
Most of the patients died; one of them was referred to her clinic to see what could
be done to correct the problem, if anything. "Double, double toil and trouble; fire burn
and cauldron bubble" (Macbeath).

Ken Lee

27-Jan-2011, 17:35

http://www.kenleegallery.com/images/forum/deadhorse.gif

It appears that everyone has had a chance to share their opinion and well-meaning advice :)

Roger Cole

27-Jan-2011, 18:23

Thanks Ken.

onnect17

28-Jan-2011, 00:15

...touching a single drop of Parathion is fatal...

Drew,
Thanks for bringing to the attention the importance of using protection while being exposed to dangerous enviroment (I guess Castro's area in SF could use the benefit)

But some part of your statement I can tell you is not 100% true.
Few decades back Cuba was affected by a epidemy transmitted by mosquitoes.
The only way to control it was to attack the mosquito population and during months every single day at sunset a number of planes, pickup trucks and workers with backpacks spent a couple of hours fumigating guess what "parathion". You could feel it in your skin and smell it. Still I never heard of anybody inside or out the country suffering of any damage.

I'm sure is toxic but touching a single drop is NOT fatal.

rdenney

31-Jan-2011, 06:05

Okay, guys, it's a matter of calculated risk. Yes, there are many substances we deal with every day that are toxic. But refusing the convenient use of simple protection for one of them just because we aren't protected from others seems a bit like justifying a sugary drink to go along with our fatty doughnut. One could say that there is no sense in worrying about the sugar if one is going to eat the fat, but one could also say that the worst thing one can do when eating a fatty doughnut is pile on another few hundred empty and nutritionless calories from a sugary drink.

I live in an area with relatively high radon concentrations. Radon is a naturally occurring substance with wildly varying opinions as to its dangers. One thing seems obvious to me: There is a lot more cancer in this part of the country than where I lived before. I don't know what caused it, and I have no idea whether radon was a contributor. Maybe it's the water, or the gene pool, or the research done in this area, or the exposure to political blather. Anecdotal? Of course. But it is also anecdotal to claim there is no effect, if it hasn't been carefully studied in large populations. And even then, risk in large populations says little about risk in individuals. (I know a thing or two about statistics.) Since such studies haven't been done, it only makes sense to take reasonable precautions, on the off chance that the concerns are real. Putting in a ventilation system to prevent the buildup of radon is a lot less convenient (read: expensive) than using rubber gloves when handling darkroom chemicals. But doing it just seemed like a reasonable precaution.

Rick "whose grandfather-in-law, a career NIH scientist, died untimely of Parkinson's, and who lives just down the road from Fort Dietrich" Denney