Pyro

[Scyg]

I've been reading a lot of praise about pyro developers, particularly Pyrocat HD. I've also seen some really stunning images where it was used as a compensating developer with limited agitation to hold almost impossible-looking highlights in. But I'm also seeing a lot of people using them in rotary systems as their regular go-to developer. So my question is whether pyro has any advantages over HC-110 or even D-76 when not used as a compensating developer? Or am I just missing something entirely?

[Vaughn]

For printing using processes requiring exposure with UV light, the stain blocks some UV. Since the stain is greater where there is more silver, it adds contrast that many of the processes needs. At the same time, the stain acts as a low-contrast filter so the same negative can be used for silver printing on VC papers. So it is possible to use the same neg for silver printing and alt printing.

[esearing]

For me Pyro allows more subtle control than I have with HC110, especially when I need to expand or contract the negative. You can use it diluted with minimal agitation, stronger for rotary, or as a standard developer even with single sheet development. Key is to zero in on dilution and time for your needs.
my 1liter of HC110 is 5 years old, half full, and has turned toward orange but still works. I use it mainly for roll film.

[sperdynamite]

I’m just getting into a Pyro developer too. It’s been interesting. I tried to make a curve for Catlabs X film in 510-Pyro but I don’t think my Heiland TRD-2 can properly read the stain. My zone I density is fine but I can never “read” a high enough zone VIII. However the negatives look very good and print well so I just called it good. I have read that a blue reading densitometer is better for Pyro... The negatives are beautiful and the compensating effect is very good. I won’t say it a a magic bullet though. I still use replenished XTol for large format negatives and they’re really special too. I finally tried Pyro because some of the best prints I’ve seen from others were made from Pyro negatives so, had to give it a go!

[Alan9940]

There is nothing special about pyro developers over "normal" developers like HC-110 or D-76. That said, what I like about pyro-based film developers is:

1. In the field, I know I can push my exposure a bit to hold necessary shadow detail because I don't need to worry about the high values dropping off the upper end of the curve; especially when using a minimal agitation technique.

2. Pyrocat-HD negatives seems to be tailor made for printing on VC papers and they print easily and beautifully.

3. When using pyro developers for smaller format film--120 and 35mm--the stain tends to hide the grain.

4. I make pt/pd prints, too, and the UV blocking capability of the stain means that I don't have to "cook" the film to achieve the needed CI for this printing process.

But, pyro-based developers aren't without issue and/or concern. You will need to concern yourself with oxidation, it's poisonous, it will stain just about anything it gets on, quality of the product can be problematic (unless you mix it yourself), and I've had the developer die on me unexpectedly long before its anticipated shelf life. Therefore, there are things to think about with pyro developers. I'd suggest reading up on these developers--Sandy King articles on unblinkingeye, for example--before embarking on using them.

[Pere Casals]

I've also seen some really stunning images where it was used as a compensating developer with limited agitation to hold almost impossible-looking highlights in.

This is not the Pyro developer, this is a photographer mastering his tools. A similar effect can be obtained with other developers or with other tools. It's the indian and not the arrow. No magic bullets out there.

So my question is whether pyro has any advantages over HC-110 or even D-76 when not used as a compensating developer?

The pyro stain effectively "modifies" the paper's sensitomatric curve, but only if it's a Variable Contrast paper. This does not happen with graded paper.

Look, we have general stain and proportional stain, general stain is like fog, this is a certain amount of uniform stain in all the negative.

Then you have the proportional stain, which is the aditional amount of stain an spot has that is "proportional" to the silver density. So the density an spot has in the pyro negative comes from two sources: Density provided by developed metallic silver and second, density provided by the stain.

Then it happens that those spots having a high density also have more stain, and stain is yellowish or greenish so it blocks more the blue. So those spots with higher density have a yellow filter on them, so those spots print with a lower contrast in a variable contrast paper.

The effect consists in that stain also provides a Contrast filter (like those graded from 00 to 5) that is locally more intense in the highlights, so highlights print with a lower contrast, so it's easy to print those highlights, reiterating it...

Depending on the pyro formula that effect is more or less intense.

Sandy King, inventor of pyrocat, has explained this:

..."Brown stain blocks green light more effectively than green stain, and for that reason there is much less shouldering in the highlights with Pyrocat HD than with PMK. The result is that prints made with Pyrocat-HD negatives on VC papers will have more contrast in the highlights than prints made with PMK negatives, but there will less compensating effect."

(https://www.largeformatphotography.i...l=1#post141945)

So he says that HD is less compensating than PMK. By adjustig the stain we adjust that effect.




If you are to scan (hybrid) all that is irrelevant, because you bend the curve like you want. If you are to print on graded paper this is also irrelevant because graded paper has little response to light color. But if you print on VC paper you are to notice that effect.

The same effect can be obtained with a long toe Cl paper like Lodima or Lupex. You also obtain the same by using a more shuldered film or a more compensating processing.

Many people praising TMax linearity in the highlights later may have problems in optically printing highlights, because those highlights are very dense, the stain allows an easier printing of those highlights.


So... practice, test, master those techniques... and make nice optic prints !!


Personally I'm experimenting with generating color masks including some artificial stain to control contrast locally, still refining that method:

https://www.largeformatphotography.i...-curve-control

[Drew Wiley]

Pyro controls highlights via proportional stain. What a compensating developer does is something different, but pyro can be formulated that way too. I've tried numerous pryro formulas as well as concocting a couple special tweaks of my own. I prefer PMK pyro based on pyrogallol to Pyrocat HD based on pyrochatechol for tray use and hand-inversion drums, but there are better choices for the higher oxidation risk of automated rotary drums if one goes that route. There are many past threads about pyro and some get pretty heated. I wouldn't make too much of a fuss about it and just pick a popular formula and learn what it can do. I've found pyro stain to work equally well for graded and VC papers. PMK gives a slightly greenish-yellow stain, Pyrocat yellowish-brown. As Pere noted, Tmax films have quite a bit of straight-line linearity, but if the highlights are too dense, that's simply due to either overexposure or overdevelopment just like any other film. Some people don't trust the straight line deeper down into the shadows with TMax films, so place their shadow values too high on the scale, and then risk overexposure at the upper end. The problem is not with the film, but them misunderstanding it and trying it force fit it into some rigid Zone System stereotype pair of shoes that are too small.

[jp]

It's cheap, it's versatile. It does a great job. I like the stain for making single negatives good for alt process and normal silver and scanning purposes. Grain is less visible due to the stain. It's xtol or d76 good for in terms of fine grain. It saves me time to make developer once a year because a L of concentrate will last a very long time compared to d76 or xtol which is used straight or 1:1. I like to process film or make prints rather than spend time mixing chemicals.

The concern about the poison is the powdered chemical raw ingredients potentially being airborne and inhaled or otherwise contaminating your darkroom. I mix my concentrate outdoors once a year or slightly longer since the concentrate lasts well in glycol and no room for air/oxygen in the bottle. In normal use, I don't have a need to touch it. It's dispensed, stirred into water, and dumped into a tank. Then it goes down the drain after use without further touching. Once it oxidizes, it's something harmless.

I use mostly pyrocat hdc. It's functionally the same as hd, but one less ingredient, so it's easier to mix.

[Drew Wiley]

If one is worried about mixing powder, A&B liquid concentrate kits are available from Photographer's Formulary and certain other sources. I find the liquid kits convenient and still economical. I use nitrile gloves for everything in the sink room, regardless. Pyro can be toxic, but ordinary metol can develop itchy skin rashes, and fixer on fingers can get onto who knows how much else; gloves rinse off easier and protect you from all the above.

[Scyg]

Wow. Thanks everyone. This is great. I haven't done alternative printing since college (many moons ago), but having a versatile negative like that can't hurt, just in case the 19th century gods move me in the eggy direction once again. I think I'll start with Pyrocat HD and work my way out from there if I like it.