[pure-silver] Re: Anti-Silvering Agent
- From: "BOB KISS" <bobkiss@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Mon, 30 Apr 2007 07:43:53 -0400
DEAR RICHARD,
Thanks for this info! As always I am wondering about quantities to
add per liter of stock or working strength dev.
CHEERS!
BOB
-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Richard Knoppow
Sent: Monday, April 30, 2007 2:26 AM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Anti-Silvering Agent
I've come across another patent that may be of some interest to the
group. This one is USP 3,161,524 issued to Richard W. Henn and assigned to
Eastman Kodak. In it Henn describes the use of Chlororesorcinol as a silver
sequestering agent to prevent dichroic fog. He gives results using high
solvent developers, in particular Kodak D-25 with and without the addition
of the Chlororesorcinol which show that a relatively small amount of this
substance completely eliminates the deposition of silver on the surfaces of
high speed film.
I think it is possible that Chlororesorcinol may be the "X" in
Microdol-X and its presence may be the difference between T-Max developer
and T-Max RS. Kodak does not recommend the use of T-Max for sheet film due
to dichroic fog.
Those with a better knowledge of photographic chemistry than I may want
to have a look at this patent.
--
Richard Knoppow
dickburk@xxxxxxxxxxxxx
Los Angeles, CA, USA
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