U of S | Mailing List Archive | alt-photo-process-l | Re: archivalness of gum

Re: archivalness of gum

Whew Ryuji, this is very esoteric though perhaps near exact.
Hidden within my description is the fact that ONCE the colors were achieved,
whether through a water based release or benzyl alcohol, the colors formed could
be protected through some chemical path. In other words, the dyes formed could be
destroyed through UV interactions (my presumption) . . . like today's sprays, which
ward off UV destruction in digital prints . . . could be protected by a 'shield'. The
'shield' then was partially cleanliness via thorough washing and removal of chemicals
of destruction like the thiosulfates, but it was also the formaldehyde, which hardened the
dye cloud, protecting it. My theory, which seems to be substantiated due to the 1960's
images being still here and with not bad color though kept in drawers, is that I used then
a hypo-eliminator and washed twice as long and hardened w/formalin (which, oddly, I
still have).

On December2007, at 10:37 PM, Ryuji Suzuki wrote:

From: jfulton <jfulton@sfai.edu>
Subject: Re: archivalness of gum
Date: Thu, 20 Dec 2007 15:09:55 -0800

the Agfa color paper I had used, which was a Type B VS
Kodak's Type A material, was the worst ever in the history
of color photography for fading etc.
there once was two 'types' of color paper: Kodak's w/an
encapsulated color coupler released by benzyl alcohol as I
remember and the Agfa type that was water based. The water
based material faded quickly. I wonder if they made it
today, like our greatly improved latex paints, if they might
last longer and be safer to the environment.
The short answer is they probably don't want to make such
materials using water dispersible couplers. The water
dispersible couplers are, due to their molecular structural
limitations, difficult to make such that the dyes formed will
have nicely narrow spectral absorption characteristics. They
are also difficult to synthesize and particularly
purify. Inferior permanence would be largely the same as what
you experienced, as well, though this one might be possible to
improve it if they try.

There is another type of couplers, that are sometimes used for
magenta couplers. The couplers are immobilized by

The solvents used to disperse oil-soluble couplers are almost
completely recycled within the film factory. Some organic
solvents of high boiling point are used to disperse the
couplers, and then this dispersed coupler is emulsified in the
base silver gelatin emulsion using
dispersants/emulsifiers/surfactants. Therefore, overall, the
vast majority of the solvents is water.

Ryuji Suzuki
"Make something religious and people don't have to deal with it, they
can say it's irrelevant." (Bob Dylan, Biograph booklet, 1985)