Hi guys and gals. After a fairly stressful year, I'm finally going to get back to pt/pd printing - at least until the next crisis hits. My ferric oxalate will be 2 years old next week. It's been refrigerated the whole time. Should I give it a try, or just dump and start from fresh made?
Is it liquid, or powder? If liquid, I'd toss it even if refridgerated. If it is dry powder, then it should still be good.
I just mixed up some that was 4 years old. The unused bottle sat in a cupboard in my darkroom. No issues that I could see. Is it still a greenish colour?
It's the liquid - looks fine. I do have some powder, so can mix up more. It's just hard to dump a bottle of chemicals I barely used.
Scott is right. Dump it. Ferric Oxalate is so much cheaper than platinum or palladium, and by the time you've worked out that it is stale you will have wasted a much larger value of noble metals.
When I've accidentaly used old FO in the past, it has given a patchy, washed out print. Very ugly and a complete waste.
If it works at all, it will be grainy, unresponsive, the contrast will be way off, and as Ian said, most importantly you'll have wasted several dollars worth of platinum or palladium to prove that a few cents worth of Ferric Oxalate wasn't good anymore. The dry powder keeps a very long time. Once dissolved into solution, it's got about a six month to one year lifespan.
Yeah, I figure it would be penny wise and pound foolish to try it out, so I've mixed up a fresh 25ml. 2 years ago I mixed up 100 ml, and barely used a tenth of it. Might have used half, if my life hadn't kept interfering with my photography. I'll stick to 25ml at a time from now on. Can always mix up more if I use it up before it's best-by date. Turns out it is sunny this afternoon, rather the the rain that was predicted. I'm gardening while the FO cools and (hopefully) finishes dissolving.
