Old Chemicals (RE: ferric oxalate)
Judy, I am just going through the forgotten alt list; yes I have been busy
with other things lately. I have some chemicals that have lasted several
years, that work just fine and other that are not so good. It depends on
what they are and the best place to ask would be a chemical supplier like
ArtCraft or a major supplier. Of course because of the unforeseen issues
involved we probably all come down on the side of caution over pushing
boundaries. Some compounds are more stable than others and some more
problems to excessive moisture.
A 60 lb supply of Potassium Carbonate can get used up easily within a couple
of years if you make a bunch of prints. Here we are talking about 30 gallons
of developer from those 60lbs. However, 25 kg of ferrous ammonium sulfate
could be tough for someone to use up. I was recalling that 500g FAS produced
about 250ml of ferric oxalate, but I need to review a note book on that.
I do have a few plastic bottles of various things for toning this, or
reducing that, or... As I have been doing less and less silver gelatin
lately they are still on the shelves of the cabinet undisturbed.
I would also look at the MSDS sheets and see if there is any caution
Eric Neilsen Photo
4101 Commerce Street, Suite 9
Dallas, TX 75226
From: Judy Seigel [mailto:email@example.com]
Sent: Wednesday, November 12, 2008 4:26 PM
Subject: RE: ferric oxalate
On Mon, 10 Nov 2008, EJN Photo wrote:
> ... The cost does go down very fast AFTER the quantity of
> raw chemicals goes up a bit. If you just get 500 g of Ferrous Ammonium
> Sulfate, that might be around $65 but a 2.5 Kg is only $ 105 or so and
> is cheaper still. Artcraft might be able to repackage it if enough people
> wanted to get some.
Eric and company: What do you know about the keeping qualities of
chemicals in general when they're bought in bulk but not used right away?
I recently, for instance, threw out a large hunk of ferric ammonium
citrate because it had turned into just that -- a really hard, solid hunk.
It could have been 5 years old, but was well packaged (tightly wrapped in
supposedly air and water tight plastic)... Anyway, I was suprised.
Now there's talk of, for instance, 60 pound supply of whatever -- would
you use, say a pound a month? That could still be 5 years... On the one
hand, I'm using an old supply of ammonium dichromate, maybe 30 or 50 years
old, and it seems fine... but on the other, there was that FAC. Is there
any general info on the topic ? Is it reliable ?