Does the color of the PMK stain make a difference?greenspun.com : LUSENET : B&W Photo - Film & Processing : One Thread
I've been continuing to experiment with Sandy King's Pyrocat-HD developer, alternating between it and PMK. Soon I will publish my findings, including developing times for various films. Pyrocat behaves almost exactly like PMK, except its stain is a different color, and the staining action takes place during development rather than after. In addition, there is no problem with uneven development using Pyrocat, so you can agitate or not as suits your needs. This weekend I plan to do some serious printing with my Pyrocat negatives to see how their gradation is.
I would like to draw on the collective experience of the PMK users on this forum. How important do you think the green color of the stain is? One correspondent states that it is critical for printing on VC papers, since it holds down contrast in the high values. Someone else seems to think reducing high value contrast is a drawback. One person recommends never adding amidol to PMK, as it changes the color of the stain (more brown/black and less yellow/green). Someone else states that a well-known photographer recommends always adding amidol.
Also, how critical is it to not use an acid stop, washing aids, and acid fixers? I have always used a brief acid stop, and I continue to use regular high speed fixers--I don't seem to have a problem getting stain in my film, but many people have posted that an acid environment will reduce the staining action. Does this come from a seminar you have attended, or from a later edition of THE BOOK OF PYRO? I own the first edition, which doesn't really address these factors, except to recommend an alkaline afterbath.
Please tell me if your opinions/recommendations stem from your own experience, or if they are from some authority or book on the subject.
-- Ed Buffaloe (firstname.lastname@example.org), May 24, 2000
, how critical is it to not use an acid stop, washing aids, and acid fixers
Ed, the only time I can say I noticed a real difference is with Technical Pan. When I stopped using an acid bath and switched to F24 (alkaline fixer), I noticed the stain went from, well, barely existent, to a fair amount more present (thought TP doesn't stain greatly in my experience...).
-- shawn (email@example.com), May 24, 2000.
My understanding is that it's the yellow component of the yellow-green stain that acts like a low contrast filter for variable contast paper. And, in the 3rd printing of Gordon's book, he goes into great detail about keeping the developing process entirely alkaline (developer and fixer) or neutral (water stop and wash). He recommends the Formulary's TF-4 alkaline fixer for maximum stain.
-- Brian Hinther (BrianH@sd314.k12.id.us), May 24, 2000.
If I use water to stop and TF4 to fix, I get just as much stain without the afterbath as with it (subjective eyeballing, no densometer readings to back that up.) Saving that time isn't critical to me, not having to save and repour the developer is nice though.
I don't know about stain color, since I've only ever gotten the normal yellow-green one.
-- Paul D. Robertson (firstname.lastname@example.org), May 24, 2000.
I think the color of the stain is important because of its effects on variable contrast paper highlight rendition. The grainless density that the stain contributes to the negative would seem to be an additional benefit but I don't think the color would matter there.
I'll be interested to hear your results with the Pyrocat version.
-- Don Karon (email@example.com), May 29, 2000.
Ed, Since you plan to publish your results, I would suggest that you borrow (if you don't have) a good color analyzer and measure the RGB or CYM values with and without the pyro stain. I would suggest using three negatives, with light, neutral and dark gray (gray card, plus and minus 2 stops, no other image) with a neutral gray processed in normal non-staining developer as the control. This will give reasonably quantitative data on the shift in color, and some indication in shift in hardness of prints on VC paper. Of course, if you enjoy this sort of thing you could expand the testing considerably, but I think you would rather make photos.
-- Richard Newman (firstname.lastname@example.org), May 30, 2000.