From: Judy Seigel <jseigel@panix.com>
Subject: silver plating
Date: Wed, 16 Nov 2005 23:36:56 -0500 (EST)
> AFAIK there's no dye in paper... I stored used PRINT fixer in gallon
> plastic containers for future extraction of the silver and/or disposal..
> With well-used fix there arrived in due course a heavy black deposit on
> the sides, which, by whatever mechanism, must have been silver.
Where did you hear that?
Fact: Dye is very commonly used in enlarging papers. (All variable
contrast b&w papers, all color papers, and some graded papers.)
The only way I know of to get black silver out of used fixer, without
using any additional chemical or electrical means, is to evaporate the
water. This is a lot easier to do with ammonium thiosulfate fixer than
sodium thiosulfate fixer. But then the precipitate will be a mixture.
Received on Thu Nov 17 14:18:51 2005
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