From: Ryuji Suzuki (firstname.lastname@example.org)
Date: 10/31/03-11:47:26 AM Z
From: Sandy King <email@example.com>
Subject: Re: Test for Silver Metal in Print?
Date: Fri, 31 Oct 2003 10:17:26 -0500
> I have to agree with this, and may I add that I am somewhat surprised
> how little valid literature there appears to be on the subject of
> toning. Or for that matter, how little is understand of the exact
> nature of the reaction.
It's not just toning. With a bit of cynicism, I say that a lot of
darkroom literature are cut and paste work of old literatures, maybe
with added modern misconceptions. Old literatures are filled with all
sorts of magical statements, some from lack of scientific knowledge at
that time or simply from plain enthusiasm about particular technique.
Stories get embellished by playing with words without going back to
the underlying process or mechanism. If I sound too cynical, that's
because I too was initially fascinated by those implausible stories
and took a lot of time and effort to find out.
Silver gelatin process is somewhat fortunate because it was more of an
applied science than alchemy in later half of the 20th century in R&D
side, with great scientific and industrial interests. Toning process
was mostly completed before photographic R&D efforts took this style,
and whatever that was known to work well enough continued to be
used. There are some modern literature on this topic, but mostly
focusing on sulfiding and selenium toning because sulfiding allows
maximum permanence with minimum cost, and selenium toning was once
thought to give complete protection against oxidative attacks due to
peroxide with minimum hue shift. Yet the quantity and depth of
publications of these topics are far less than those on physics and
chemistry of silver-halide compounds, photographically active dyes,
etc. that are more "important." So there is no surprise for lack of
modern research in palladium or platinum toning.
Disappointing? Maybe. To me it's more disappointing to realize that
digital photography is taking over industrial importance before all
important questions of photographic chemistry and physics are
answered. At this point, my opinion is that it is more important to
maintain and make available the established knowledge to those who
need it in the future at various levels, including ones who need to
communicate with chemists and physicists. I also think there is a need
for more update and complete resources for those who make silver
gelatin emulsion as an alternative process.
-- Ryuji Suzuki "Reality has always had too many heads." (Bob Dylan, Cold Irons Bound, 1997)
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