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
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