pyro developer, but which?

[kev curry]

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

[Bob McCarthy]

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]

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]

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

[Jay DeFehr]

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]

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]

Thanks for the kind offer Jay. Cheers!

[Fred L]

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

Henry Yee ?

[sanking]

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]

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