How to verify that I fixed properly and washed properly

[darkroommike]

A drop of selenium toner in the margin of a print is a good test for proper fixing: https://www.photrio.com/forum/threads/selenium-toner-as-fixer-test.68246/

Thanks, exactly what I would have said.

 

[darkroommike]

A couple more thoughts (I may be close to my limit for good ideas for this week but here goes).

1. As you fix film you are converting silver halides to silver thiosulfate compounds. Then you wash the silver thiosulfates out of the emulsion, but here's the "gotcha" FRESH fixer produces silver thiosulfates that are more soluble than the silver thiosulfates produced by tired or exhausted fixer. Someone with a better grasp of the exact chemistry can number how many different silver thiosulfates there are but there are at least 4 to maybe 6 common ones, some are much less easy to wash out than others.
2. This is another reason why archival processing uses a first bath that is partially used and does all the "heavy lifting" (90% of the fixation process) and then a second very fresh bath that changes the less soluble thiosulfates back into their more soluble cousins.
3. Production labs do chemical monitoring with test papers and reagents, they also process "control strips" and employ densitometers and sensitometry to keep on top of their chemistry and can tell when the developer needs more/less replenishment or is going bad or the fixer needs more replenishment. This takes time and money. You and I are better off to just use simple tally marks and track average use with that and dump chemicals on schedule. Other folks here and in the lab probably process enough film and paper to also make is worthwhile.