Re: silver plating

From: Richard Knoppow ^lt;>
Date: 11/17/05-03:12:41 PM Z
Message-id: <004901c5ebbb$a8b8eb30$97fb5142@VALUED20606295>

----- Original Message -----
From: "Ryuji Suzuki" <>
To: <>
Sent: Thursday, November 17, 2005 12:18 PM
Subject: Re: silver plating

> From: Judy Seigel <>
> 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.
   Perhaps some clarifications would help. Ryuji, you talk
about black silver, presumably metallic silver, is that
correct? Silver recovery from fixing baths can be done with
steel wool (standard method), it (or something) will be
deposited on fresh copper, like clean pennies, soaked in the
fixer. Is this not silver?
   Is it possible the black deposit Judy talks about is
sludge from bacteria?

Richard Knoppow
Los Angeles, CA, USA 
Received on Thu Nov 17 15:13:26 2005

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