Re: Preserving photo chemistry

Keith Dowsett (kdowsett@rpms.ac.uk)
Wed, 18 Dec 1996 09:09:49 -0100

>Here is an old "trick" I was taught a long time ago. After pouring some
>developer out of a bottle, breathe into it (that is, exhale) before resealing
>it. The idea is the carbon dioxide in your breath will displace the oxygen.
>I would think that an "inert" gas would work even better.
>
>Bob Schramm

When you breathe you only convert a small proportion of the oxygen in the
air to carbon dioxide. This carbon dioxide will react with the alkali in the
developer reducing the pH very slightly.

I would suggest using an 'air' canister like the one used for cleaning the
negs. These contain one of the freon group compounds (usually HFC134a) which
will displace the air and reduce oxidation.

Keith.
==========================================================
Keith Dowsett "Variables won't; constants aren't."

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