Re: silver plating

From: Judy Seigel ^lt;>
Date: 11/17/05-10:01:35 PM Z
Message-id: <>

On Thu, 17 Nov 2005, Ryuji Suzuki wrote:
> Fact: Dye is very commonly used in enlarging papers. (All variable
> contrast b&w papers, all color papers, and some graded papers.)

The paper was old Brovira, grade 5 or 6 for the most part, and certainly
SHOWED no dye in an unexposed undeveloped sheet. Unable to cite "theory"
which is here *asserted*... I can only say I OBSERVED a thick deposit
which looked quite like the deposit I got when adding steel wool (exactly
for the purpose of precipitating out the silver so I could throw the rest
of the fix down the drain), an amount, whatever theory is reached for,
that could not have accumulated from the invisible dye in the white paper
-- not even a truckload of it.

> The only way I know of....

As Shakespeare said "there are more things in heaven & earth,
Horatio, than...." whoever it was dreamed 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.

It was NOT evaporated, but just as it came from the 2nd tray. Heico NH
5, which was (as I recall, it being 18 years since I used it) ammonium --
but no hardener.

Received on Thu Nov 17 22:01:47 2005

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