The question I raised about the influence of reciprocity departure intrigued me enough that I decided to run an 'end points' test yesterday. I have a perfect SBR 13+ stairwell in my house with a window that has even open shade illlumination from outside. I used some neutral density filters to allow me to make two different lengths of exposure on Tmax400. Exposure #1 was 16 seconds, just barely into the reciprocity failure zone with this film, and # 2 used a 5 stop combination of N.D. filters to make another exposure at a calculated 'correct' time of 25 minutes. My thought is to develop the two sheets of film together in my jobo to the same theoretically correct gradient of .38 to achieve my normal density range of 1.4 that I use with pyrocatHD and my palladium printing process, and see if I can detect any differences in shadow contrast. The negs are 5x7, so I will be able to use a densitometer to pull out some quantitative data from the shadow areas to compare between the two. Does this sound like a reasonable sort of test to run to chase down this idea?(posted 8169 days ago)One other compensating development approach that I have read about but have yet to try is the one that Mark Citret espouses for his high SBR images. He has a full description in an article on his web page, but in brief, he uses the extreme dilution approach just suggested by Ryuji with much extended times. His preference is Rodinal at 1:149. His theory is that highlight development needs 'energy' (i.e. chemical concentration) and shadow development just needs time. Check out his web page at www.markcitret.com. He has some great images to browse through. Wanted to emphasize that last part, since all this is great fun, but if it doesn't result in some interesting images, then its sort of pointless.
Great thread.
A totally unrelated question to someone on this thread. What is the solubility of glycin in water? I'm trying to mix up a glycin/ catechol soup and the glycin is very difficult to dissolve. And should the glycin be mixed first, or after the solution has a higher pH?
Clay