Pyro question?

[stradibarrius]

I have never used Pyro. I use either HC110 or Rodinal. I have been very happy with my results. What advantages does pyro have over these two developers? Are there certain situations that call for pyro?

[mikebarger]

For me I like skies and clouds better with 510 Pyro than HC110. However, if HC110 was all I had I'd still be happy. I shoot HP5 in LF and Tri-X 400 in 120mm.

[Andrew O'Neill]

Using a pyro developer enables me to print the negative on gelatin silver papers or alternative processes, such as carbon transfer printing. HP5 negatives print beautifully on gelatin silver papers but I have never been able to get the same negative to print well in carbon. Extended development only drives up the b+f, increasing the alt process exposure time resulting in ugly, veiled shadows. I have no problems with FP4 and TMY-2.
Anyways, you will notice much smoother tonal transitions especially in the highlights, less grain. The negatives will look slightly thinner than conventionally developed negatives (you should back off on development due to the stain density) and scan beautifully.
Another thing about pyro (I use pyrocat-hd) is the ability to do stand or semi-stand development for enhanced edge effects.

andrew

[Gem Singer]

Gordon Hutchings contended that it's impossible to blow out the highlights when using a Pyro developer.

My technique is to rate the film at box speed, spot meter, and place the shadow areas, where I want some detail, in Zone III. Then, develop normally.

The highlights were very difficult to print when I used a robust developer like HC-110, or DD-X.

No more blown out highlights now that I have switched to Pyrocat-HD.

[bob carnie]

I would say that he was almost right, I have seen a few impossible neg's to print using Pyro developer but not many.

Gordon Hutchings contended that it's impossible to blow out the highlights when using a Pyro developer.

My former technique was to rate the film at box speed, spot meter, and place the shadow areas, where I wanted some detail, in Zone III. Then, develop normally.

The highlights were very difficult to print, especially I used a robust developer like HC-110, or DD-X.

No problem now that I have switched to Pyrocat-HD.

[Andrew O'Neill]

That's a good point, Gem. So very true.

[Jay DeFehr]

Barry,

this a "can-O-worms" kind of question, but my opinion is that a developer should be judged by its total IQ pkg, and not for any single characteristic, unless of course you have something very specific in mind. I also think choice of developer for LF is a special case with different requirements from small formats that are enlarged many times the size of the negative, and just about any developer will produce acceptable results for most users, under most circumstances.

Long scale UV printing processes favor pyro (staining/tanning) developers, because of the increase in contrast provided by the image stain, but the staining developer shouldn't produce excessive general stain, which would defeat the advantage.

Situations in which highlight compression is an advantage also favor a staining developer, provided the neg is to be printed on VC paper. Stained negs will always print on VC paper with a split-grade effect -- more contrast in the low values than in the high values.

Some users claim scanning favors staining developers, but I can't say that's true or false, and defer to those with more scanning expertise, which is just about everyone. In my limited scanning experience with low end consumer scanners, I don't see much difference, but that's hardly surprising.

My all-time, all-purpose favorite developer is 510-Pyro, because it does everything so well, and so dependably, BUT for maximum overall IQ, nothing I've ever used beats Halcyon, a non-staining ultrafine-grain developer, used in a replenished system.

[Jay DeFehr]

There were a few posts while I was (slowly) writing mine. To Hutchings' assertion that it's impossible to blow out highlights using a staining developer, I say, nonsense. When printing on graded papers, the stain increases contrast geometrically, and it's very easy to blow highlights with an energetic staining developer like ABC Pyro, or 510-Pyro. I've regularly developed films in pyro developers to densities above log 3.0. Not all pyro developers are compensating developers.

[cdholden]

Jay,
Can you elaborate on geometric increase of contrast? Is that like a linear/proportional comparison?
Without having any tools to measure or calculate density, I only have my own negatives and a naked eye for comparison in the trial and error game. Having some numbers or relationship may help, but I just try to get a successful print one negative at a time. I've found (after your suggestion) that graded papers do help with consistency in the final result.

[Jay DeFehr]

Hi CD,

By geometric I mean that the increase in stain density is not linear relative to the silver density, but proportional to it. If we plot two curves -- one for silver density, and one for silver + stain density -- the two will diverge at some point, near the toe (for most developers). The gap between the two curves will increase with increased density, at a geometric rate. This is a little confusing because contrast always increases at a geometric rate, which is just what a characteristic curve represents, but the deviation from the silver-only curve is also geometric.

So, it's not only possible to blow highlights, but an inevitability given excessive development, which is a bit circular, since excessive development is defined by blown highlights.

Like so many other pyro myths, there is a grain of truth in this one. To the extent that a pyro developer is a compensating one, there is a tendency for it to protect against runaway highlight density. This protection is not conferred by the stain (except when printing on VC papers), but in spite of it, by the tanning action of the developer. Tanning developers harden the emulsion in proportion to exposure just as staining developers stain in proportion to exposure. As the emulsion hardens, access to it by fresh developer is restricted, creating a braking effect in the highlights, or compensation. Proportional stain, as described above, works in direct opposition to the compensating effect of tanning.

For example, Obsidian Aqua is a compensating/ tanning/ staining developer. The braking effect on highlight density by tanning is enhanced because it is a single agent developer that does not regenerate in solution, and because it's used in a very dilute solution, with intermittent agitation. By adjusting the ratios of the 3 ingredients in OA, one could make a highly compensating, and non-staining developer. An increase in the metabisulfite (which creates sulfite in combination with the carbonate) eliminates the stain, and the increased highlight density along with it, but retains the tanning responsible for the compensating effect. There will also be an increase in the appearance of grain because the grain-free stain portion of the image density is replaced by silver density.

You might also be able to infer from the above how image stain decreases film speed. A fascinating and complex subject, as always!

[minesix66]

Hi, I was planning on purchasing the Pyrocat HD pr the Pyrocat HD with Glycol and using it to develop my TMAX 100 and Fuji Acros 100, 4x5 films. Is the recommend 9 mins 36 secs @71 degrees, a good idea for my films. I took pictures of water falls with very low light, cloudy day. The average time on my meter stated 1-4secs to take the pictures. I plan on using TF-4 for the fixer and plain water for the stop. Any info would be appreciated. I really don't want to screw up these negatives. I will be using a Jobo CPE2 with the motor speed set at 1. I am looking for smooth tones in the shadows and sharpness. I will be mostly scanning the negatives, I might try to darkroom print in the future.

[Ken Lee]

"What advantages does pyro have over these two developers? Are there certain situations that call for pyro?"

You might find this article interesting: An Introduction to Pyro Staining Developers, With Special Attention to the Pyrocat-HD Formula (http://unblinkingeye.com/Articles/PCat/pcat.html)

[Kirk Gittings]

You lost the link Ken.

FWIW I find PyroCat HD a very forgiving developer. Where did that recommended time come from? What ISO did you shoot the film at and what method of development are you using? My times are shorter but I am shooting Acros at 64 and developing with constant agitation in BTZS tubes.

[minesix66]

I found it on Google search. Past articles, Sandy King recommended it. I typed in Pryor HD 100 tmax, I read that Pyro isn't recommended for tmax 100. I shot all film at box speed, ISO 100. I am using the Job rotary processor.

[bob carnie]

Great Post Jay

I have always felt the tanning effect was the single most important aspect of Pyro development.
Now I am interested in trying Obsidian Aqua developer.... who the hell came up with that name.


Hi CD,

By geometric I mean that the increase in stain density is not linear relative to the silver density, but proportional to it. If we plot two curves -- one for silver density, and one for silver + stain density -- the two will diverge at some point, near the toe (for most developers). The gap between the two curves will increase with increased density, at a geometric rate. This is a little confusing because contrast always increases at a geometric rate, which is just what a characteristic curve represents, but the deviation from the silver-only curve is also geometric.

So, it's not only possible to blow highlights, but an inevitability given excessive development, which is a bit circular, since excessive development is defined by blown highlights.

Like so many other pyro myths, there is a grain of truth in this one. To the extent that a pyro developer is a compensating one, there is a tendency for it to protect against runaway highlight density. This protection is not conferred by the stain (except when printing on VC papers), but in spite of it, by the tanning action of the developer. Tanning developers harden the emulsion in proportion to exposure just as staining developers stain in proportion to exposure. As the emulsion hardens, access to it by fresh developer is restricted, creating a braking effect in the highlights, or compensation. Proportional stain, as described above, works in direct opposition to the compensating effect of tanning.

For example, Obsidian Aqua is a compensating/ tanning/ staining developer. The braking effect on highlight density by tanning is enhanced because it is a single agent developer that does not regenerate in solution, and because it's used in a very dilute solution, with intermittent agitation. By adjusting the ratios of the 3 ingredients in OA, one could make a highly compensating, and non-staining developer. An increase in the metabisulfite (which creates sulfite in combination with the carbonate) eliminates the stain, and the increased highlight density along with it, but retains the tanning responsible for the compensating effect. There will also be an increase in the appearance of grain because the grain-free stain portion of the image density is replaced by silver density.

You might also be able to infer from the above how image stain decreases film speed. A fascinating and complex subject, as always!

[Mark Barendt]

Great Post Jay

I have always felt the tanning effect was the single most important aspect of Pyro development.
Now I am interested in trying Obsidian Aqua developer.... who the hell came up with that name.

I think the name is interesting, essentially "black water".

[Jay DeFehr]

Great Post Jay

I have always felt the tanning effect was the single most important aspect of Pyro development.
Now I am interested in trying Obsidian Aqua developer.... who the hell came up with that name.

Hi Bob,

Tanning doesn't get much press, though it is responsible for many of the characteristics we associate with pyro/catechol developers, and some we don't. The real magic, in my opinion, is in the combination of staining and tanning that provides a loophole in the laws of compromise that govern other kinds of developers, allowing us to formulate high acutance/fine grain developers that deliver full film speed.

Obsidian, mankind's first knife edge, is still used in surgical scalpels, and no steel can match it. Obsidian represents sharpness. OA is essentially a water-based (Aqua) version of Hypercat, which is made up in glycol. My motivation for making a water-based version was to make the developer available as economically as possible, to as many people as possible, using locally available ingredients. Metabisulfites, carbonates and water are widely available and inexpensive, leaving only catechol to ship, where it isn't available locally. 250g of catechol doesn't cost much to ship, will make a liter of OA concentrate that will develop at least 1,000 rolls of film, or equivalent, and I've done my best to give it a shelf life long enough to use every drop.

OA is good for LF, but I caution against too long rest periods during agitation -- edge effects can be dramatic. Normal intermittent agitation produces bitingly sharp negatives and ensures even development -- no need for Low Frequency Agitation. Where OA really shines is with roll films, which benefit more by edge effects and enhanced micro-contrast. OA and Acros is a favorite combination.

[bob carnie]

So where do I get some of this magical black water? I have a donated 8 x10 camera from Dave Wooten that is dying to make some big ass negatives and monster silver prints.


Hi Bob,

Tanning doesn't get much press, though it is responsible for many of the characteristics we associate with pyro/catechol developers, and some we don't. The real magic, in my opinion, is in the combination of staining and tanning that provides a loophole in the laws of compromise that govern other kinds of developers, allowing us to formulate high acutance/fine grain developers that deliver full film speed.

Obsidian, mankind's first knife edge, is still used in surgical scalpels, and no steel can match it. Obsidian represents sharpness. OA is essentially a water-based (Aqua) version of Hypercat, which is made up in glycol. My motivation for making a water-based version was to make the developer available as economically as possible, to as many people as possible, using locally available ingredients. Metabisulfites, carbonates and water are widely available and inexpensive, leaving only catechol to ship, where it isn't available locally. 250g of catechol doesn't cost much to ship, will make a liter of OA concentrate that will develop at least 1,000 rolls of film, or equivalent, and I've done my best to give it a shelf life long enough to use every drop.

OA is good for LF, but I caution against too long rest periods during agitation -- edge effects can be dramatic. Normal intermittent agitation produces bitingly sharp negatives and ensures even development -- no need for Low Frequency Agitation. Where OA really shines is with roll films, which benefit more by edge effects and enhanced micro-contrast. OA and Acros is a favorite combination.

[Ken Lee]

You lost the link Ken.

I don't follow: it works fine when I use it.

http://unblinkingeye.com/Articles/PCat/pcat.html

[mikebarger]

Works for me to Ken

[Ken Lee]

I'd love to try making some Obsidian Aqua developer.

Is this (http://photo.net/black-and-white-photo-film-processing-forum/00a1Ub) the current formulation and recommended approach ?

Is there a way to make less, with less concentration - or is that counter-indicated ?

[Jay DeFehr]

So where do I get some of this magical black water? I have a donated 8 x10 camera from Dave Wooten that is dying to make some big ass negatives and monster silver prints.

If you don't want to make your own, you can order a pre-measured kit from Artcraft Chemicals, but you'll still have to mix it. Just give them the ingredients and amounts, and they'll weigh it out for you.

OA-
Potassium metabisulfite 20g
Catechol 250g

Alkali-
Potassium carbonate 3.33kg

The above will make 1 liter of OA concentrate and 5 liters of alkali concentrate. To make a working solution of OA, you first make a working strength alkali solution by diluting the concentrate 1:100, and then add the OA concentrate 1:500.

Example:

To make 1 liter of OA 1:500 --

Tempered water 988ml
Alkali concentrate 10ml
OA concentrate 2ml

In practice, you would add 10ml of alkali concentrate to 500ml of tempered water, stir, add 2ml of OA concentrate, top up to 1 liter with tempered water, stir and use. Or, if you want to make things really simple, add 10ml of alkali concentrate to 1 liter of tempered water, stir, add 2ml of OA concentrate, stir and use. By this method you end up with 1012ml of total solution, but the error is insignificant, and as long as you mix the same way every time, your results will be consistent.

The first time you add 2ml of developer concentrate to a liter of alkali solution, it feels...wrong/impossible. After a few liters, the trepidation disappears, and the liter of developer concentrate begins to look really big.:eek:

[Jay DeFehr]

I'd love to try making some Obsidian Aqua developer.

Is this (http://photo.net/black-and-white-photo-film-processing-forum/00a1Ub) the current formulation and recommended approach ?

Is there a way to make less, with less concentration - or is that counter-indicated ?

Ken,

Yes, the formula is the same, and you can scale it down to any desired volume. Divide by 10 to get 100ml. And it can be made with potassium or sodium metabisulfite/carbonate. The potassium carbonate is more soluble if you want to make a concentrated stock solution, but it isn't absolutely necessary. As long as you end up with 6.66g/liter of working developer, it's all equivalent. And even that number is flexible. OA was tested with carbonate concentrations ranging from 3g-20g/liter, and all produced good, though different results. If you used a teaspoon of either carbonate in a liter of water, you could expect good results, and as long as your teaspoon measuring technique was consistent, you could expect consistently good results.

As far as the agitation sequence is concerned, I'm not entirely persuaded by the geometric sequence. Decreasing frequency over time makes sense, in theory, but I'm not sure it provides any benefit over more evenly spaced agitation. For a total development time of 12:00, a sequence of 2-4-8 seems reasonable, but the same sequence for a total development time of 16:00 seems less so. But, there's no reason the sequence has to be based on a factor of 2, it could instead be based on a factor of 1.4, or any other arbitrary factor that one cares to choose. I haven't formally tested for any differences in a constant frequency agitation scheme compared to a decreasing frequency scheme, but I suspect it would be very difficult to isolate any effects.

[bob carnie]

Thanks Jay I will mix some up myself and give it a go on some negs.. Jay would you recommend this with Expert tanks on a Jobo or small tank hand agitation, I am good to go for either.

[Jay DeFehr]

Thanks Jay I will mix some up myself and give it a go on some negs.. Jay would you recommend this with Expert tanks on a Jobo or small tank hand agitation, I am good to go for either.

Bob,

development times in 9:00-12:00 (70F) range are typical. OA is not meant for rotary development -- it will work, but for rotary development you're better off with 510-Pyro.

[bob carnie]

Tanks it is... thanks again

Bob,

development times in 9:00-12:00 (70F) range are typical. OA is not meant for rotary development -- it will work, but for rotary development you're better off with 510-Pyro.

[cdholden]

Thanks Jay I will mix some up myself and give it a go on some negs.. Jay would you recommend this with Expert tanks on a Jobo or small tank hand agitation, I am good to go for either.

Or trays?

[Jay DeFehr]

Or trays?

Yes, trays work fine, too.