Re: ALT-PHOTO-PROCESS digest 770

Pierre Chiha (pierre@pierre.com)
Sun, 22 Dec 1996 22:40:25 -0500

Date: Tue, 17 Dec 96 17:57:01 -0800
> From: Larry Bullis <lbullis@ctc.ctc.edu>
> To: <alt-photo-process@cse.unsw.edu.au>
> Subject: Re: Preserving photo chemistry
> Message-ID: <199612180153.RAA06262@ctc.ctc.edu>
>
> I use a lot of different developers, including color print chemicals. I
> need a very simple and also cheap method of preserving them. I have
> found a way that is pretty much ideal, at least for my purposes.
>
> Some of my friends buy wine in bulk packages, which consist of a mylar
> bag (that mirror plastic) in a cardboard box with a polyethylene spigot.
> They save these packages for me. The mylar seems to be totally airtight,
> and the poly is certainly no worse than other containers which are
> commercially available.
>
> With care, you can pry off and replace the poly seals many times. Clean
> out the bag with multiple rinses, and fill the bag while inverted, just
> as full as you can get it. Replace the seal. Then, when you draw out
> liquid, the bag collapses inside the box. No air gets back in. What
> little air might have been contained in the bag initially will oxidize a
> very small amount of the whole amount of initial filling; what gas
> remains will be mostly nitrogen - inert.
>
As a (former) chemist, the above method sounds pretty good. Adding inert
gases would also work, although I wonder how one would tell that you
have in fact displaced the oxygen. As far as which inert gas, Nitrogen
or Helium would be pretty good but I suspect that hobbyist-grade gases
contain some amount of oxygen. Freon or similar gases should be inert
for this purpose, and this would include standard air canisters found in
photo shops (look at the list of ingredients to make sure). The bag
method is probably the best, but not as convenient as inert gases.
Happy holidays
Pierre Chiha