From: "Weber, Scott" <sweber@mail.barry.edu>
Subject: blue vandykes
Date: Fri, 12 Aug 2005 15:01:59 -0400
> Does anyone have advice for combining cyanotypes and van dyke printing? I
> have seen a few examples and like the combination of colors. I tried a few
> the other day and found that the cyan on top of the vdb bleaches out the
> brown image. Any help is appreciated.
When this was brought up a few weeks ago, I suggested two possible
methods to overcome this problem. One is to use polysulfide treatment
after Van Dyke before cyano. Another is to use Fuji Ag Guard
treatment, similarly after VDB before cyano.
This bleaching is most likely due to oxidation of the metallic
silver. Unlike silver gelatin, silver is not protected by gelatin,
which makes the VDB silver image more susceptible to all sorts of
oxidative attacks. The two methods I suggested are known to make
silver more resistant to oxidation.
Received on Fri Aug 12 14:52:08 2005
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