fatso said:
Can the life of color chemicals such as RA-4 and P30 P (Ilfochrome) be extended by keeping them refrigerated (prior to mixing)? Are there any adverse effects in doing so?
Be *very* careful with liquid bleach-fix - the "prune juice" concentrate. A relatively short stay at decreased temperature will cause crystallization ... and it is damn near impossible to reverse it. There will be a whole lot of crunching going on.
I have not seen adverse effects on the color developer constituents -- but what I'm doing at the moment is replacing the air in the bottles (both color developer and bleach-fix) with butane from a Bernz-o-Matic mini torch .. and that seems to work well.
Shelf life is a problem with color chemistry. I would *really* like to use dry chemistry... so far, the only chemistry I've been able to obtain is Tetenal's Dry C-41 "Press Pak". Developed eight rolls of 120 (cheating on solution volume a bit - successfully) with one of those, and I'm happy with the results.
Tetenal DOES make dry RA-4 chemistry ... but I don't think it is available here ... I've e-mailed Tetenal a couple of times - with no reply.
Come to think of it ... I have a P-30 kit in my darkroom --- Isn't all that "dry"?