Chemical shelf life

Justin Watson · Aug 6, 2023

In general, how long do liquid chems last? Everything has been on a table in a spare room for some time. I have no clue when I bought these and certainly don’t remember when I first opened them. If I had to guess I’d say pre-Covid. Some arista. Some Kodak. One Rodinal. Some are sealed/un-opened.

I’ll probably be buying some new chems anyways. Just to make sure. But I thought I’d ask cause I’d hate to waste chems if I don’t have to.

VidThreeNorth · Aug 6, 2023

They are all "variable", mainly dependent on usage. Developer should be mixed in small batches and discarded with use. Stop bath, well, as long as it is "acidic" it is fine really, Fixer, for film I always discarded with use, but for paper, I think I used a tray for about 20-30 prints, maybe more.

petrochemist · Aug 6, 2023

Most of the pure liquid chemicals I have at work, will last for millions of years if sealed so they won't evaporate. Despite this many have shelf lives of 3 years printed on the label. A few have been contaminated by careless handling so become near useless well within a month of opening.

Liquid chemicals used for photography are typically more reactive, they will often degrade if in contact with air, oe exposed to light.
Even the less reactive ones are often solutions, where the solvent (usually water) can evaporate & change the concentration (and hence the way it works). Bad storage can ruin many photographic chemicals in as little as a month.

So there really is no in general. The best thing is to give them a go & adjust times temperatures appropriately for those that work slowly.

vintagesnaps · Aug 6, 2023

I'd probably try them on film of photos that were nothing important. Or shoot a roll of your backyard or whatever, just to try it out and see what you get. Doesn't sound like the chemistry is that old, but it's probably going to be experimental.

webestang64 · Aug 7, 2023

When in doubt start with fresh. I do but I'm also very anal when it comes to chems/film. I like fresh.

garygruber · Aug 25, 2023

webestang64 said:
When in doubt start with fresh. I do but I'm also very anal when it comes to chems/film. I like fresh.

Mixed fixer is good for 6 months. I date all of my containers so I don't have to guess. mix with distilled water, always, no exceptions. If you want to hear, I can tell you stories, I have them going back 60 years (including almost botching a National Endowment for the Arts research grant due to soft water).