Just a small update to this thread, this is about longevity and storage-options.
I had a batch of stock-solution, mixed in January 2016, just sitting on my shelf, at varying room-temperature, in a used plastic coke-bottle.
So a few days ago, I had shot some Neopan 1600 (still have 45 rolls of it in my freezer) and shot that at EI 1000 (I normally shoot it at 1000 or 1250).
Finding the bottle of Super Prodol, i decided to do a clip-test with some random, exposed film i had lying around. (It may be Polypan, I'm not sure).
Anyway, the clip-test showed a pretty good and dense strip, but not completely opaque, so I decided to mix the working solution with 3 parts developer and 2 parts water, making the ratio 1.5:1, a bit stronger than the normal 1:1 deal.
I also extended the development time for the Neopan1600 from the nominal 7 minutes, to 8 minutes.
After that, I souped some Kodak Plus-x (cine), in the now used working solution, a film which has been sitting on the shelf for about 4 months, and gave that 8 minutes too.
Yes same park, different times of the year, often go there to test stuff ^^
Negatives from both films looked denser than normal, the Plus-x the most dense, so it probably need less time in general. None of the strips are so dense that it would be an big issue printing them, the plus-x would be harder to recover highlights from, in general they are just a bit denser than normal, that's how accurate I can describe that.
Scanning talk in small letters, describing needed adjustments.
Another way to describe it, is that the Neopan only needed a slight reduction in exposure before setting the black and white points, while the Plus-x needed about 0.5 stop reduction in exposure, plus reduction/recovery of highlights and whites, as well as lowering black-point and shadows, before a final curves adjustment to regain normality.
Anyway, nothing scientific, I just wanted to make a note of how long the stock-solution keeps.
The clip-test may have been the Polypan acting weird in the developer, not creating complete black for the duration I had it in there. I did the clip-test at 1:1 working solution and possibly the time I used for the clip-test was not long enough for that film to fully develop i suppose.
The Super-prodol, based on the look of the negatives I got from this little session, showed that it was very much alive, even after more than 1 and a half year in storage at stock-solution..
I did top off the bottle with some Tetenal protectan back in 2016, and the water i used, was regular tap-water, which was run trough a Brita-filter can, nothing fancy.
Not bad at all.
Ps and note to self: Do the clip-test with the actual film in question, for the time intended