Donald Qualls
Allowing Ads
I wouldn't suggest trying to keep Parodinal for thirty years like you could do with the Rodinal sold under that name back in the 1990s and earlier. Parodinal does keep pretty well, however; I've used it up to about a year old, stored in a partly fully pickle jar with no gas blanketing or other air exclusion. If it's no darker than cola or strong coffee, it should still be good. If you buy the biggest bottle of 500 mg acetaminophen/paracetamol tablets you can find, and have a local or free-shipping source of lye and sodium sulfite, it's also very cheap to make. It's easy enough that I'd suggest sticking with 500 ml batches.
You will need a scale good for tenths of a gram or better to get the sulfite and lye quantities correct, though -- too much lye and the concentrate won't last well, too much sulfite and it'll take too long to "ripen" (if it hasn't turned pink in 72 hours, there's a problem, with excessive sulfite the most likely culprit). These days you can get tiny electronic "drug scales" with tare, many different units, and milligram accuracy up to several hundred grams for about what I paid almost forty years ago for my reloading beam balance scale (which reads in grains -- 15.4 grains to the gram -- and can be set to much better than 0.1 grain).
You will need a scale good for tenths of a gram or better to get the sulfite and lye quantities correct, though -- too much lye and the concentrate won't last well, too much sulfite and it'll take too long to "ripen" (if it hasn't turned pink in 72 hours, there's a problem, with excessive sulfite the most likely culprit). These days you can get tiny electronic "drug scales" with tare, many different units, and milligram accuracy up to several hundred grams for about what I paid almost forty years ago for my reloading beam balance scale (which reads in grains -- 15.4 grains to the gram -- and can be set to much better than 0.1 grain).
