William Robb wrote: > ----- Original Message ----- > From: "Toralf Lund" > Subject: OTish: Rodinal/Agefix keeping time, and how to know if they are > stillgood? > >> Anyhow, I was just wondering if any of you lot have any opinions on the >> *actual* shelf life of photo chemicals, notably Rodinal developer and >> Agefix fixer. I mean, I know what the official white-papers and various >> other resources on the web will tell you, but I suspect the figures >> given are generally very pessimistic. >> >> > > Unopened, Rodinal should have a shelf life similar to that of a Sea Turtle. > Once opened, I think a couple of years is possible. That pretty much confirms my suspicion. Although I noticed just now that the data sheet says it will keep for *at least* two years - rather than giving an exact limitation on the lifetime. > The concentrate does > oxidize slightly and turns dark, but it doesn't seem to affect the > performance. > Fixer has a shelf life of decades as well. Right. In this case the white paper actually says *up to* two years. But like I said, I already know that it can be a lot older than that and at least not be completely unusable. > If a little precipitate forms, > run it through a paper coffee filter. You can test fixer with a short piece > of undeveloped film. Dunk the film part way into the solution for 15 or so > seconds, and then submerge it completely. If once both sides match density, > you have your clearing time, which is also listed on the spec sheet for the > product. Fixer is considered exhausted when the clearing time is double what > it was when fresh. > OK. So I guess the morale is that I should just do a clearing time test now and then to see if the solution is still good. I can't find any direct reference to the expected clearing time in the data sheet I'm reading, though. It just states the recommended fixing time (6-8 minutes for the "standard" dilution), and that's not exactly the same thing, is it? (But maybe I should assume something like half of the lower limit given?)
- Toralf -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
