Is there a shelf life for these? Along with some darkroom gear I just purchased, were several unopened packages of these. Also, some Kodak indicator stop bath and Kodak fixer. None of the packages have any holes or tears. The powder feels loose, not clumped. Judging from some paper work I found, they may be about 4-5 years old. Also, is an unopened jug of Kodak Professional Polymax T developer. Do you suppose these are good to use?
And of course, once mixed, these developer stock-solutions will last only a few months. I would never use any older powdered chemistry beyond a labelled expiration date until first testing it against the same chemistry that is known to not be expired. I also toss any film or paper developer immediately, if the crystalline powder inside the packages when opened before mixing have even a slight brownish oxidation discoloration. My advice, if you can afford to, is simply to buy it fresh in small quantities and to always use it fresh. But you can always test older, unknown-aged kodak powder developer chemistry easily by comparing the unknown-age developer chemistry against the same brand new chemistry. All it takes is a couple of test rolls or test sheets of film. Good luck.