I'm not following you here. Of course, the double transfer mentioned above,
in the case of monochrome work, is not the same as the "double transfer"
normally used in the "traditional" process. The latter should perhaps be
called "triple transfer"
Transfer # Comments
1 Exposed tissues transferred to plexi, developed and dried
2 From plexi transferred to Soluble Temporary Support
3 When all assembled on STS, transferred again to Final
This is the method I preferred (until I ran out of hair to pull out;-))
The soluble (i.e., unexposed) gelatin washes off in the first step, while
tissue is washed off on the plexi, at about 40C. This normally would take 5
to 8 minutes. I preferred using two separate hot water baths. The first one
did most of the work, say for 4 of the 5 minutes, and got quickly saturated
with dissolved gelatin (and pigment and dichromate). In the second tray I
could see very well what was going on. Then it went to a tray of cold water
for at least several minutes. The water was changed once or twice before
the plexi was pulled out and hung up to dry, but water was clear.
When dry, the images on the plexi were transferred to a soluble temporary
support (paper coated with soft gelatin). When all assembled on the STS,
they were transferred one last time onto a final support. At that point the
STS was pulled gently off the final, and while it had a strong relief, I
dont remember seeing any dichromate at that stage on it. (How about you
Sandy?) The image and its final support get another few minutes of hot
water at about 45C to remove all soluble gelatin from the STS, and then
goes into a cold water bath. All this (wet) time water soluble compounds
are being removed from the print.
>remove the soluble support it is very yellowish from the dichromate,
>especially where the dark parts of the image were. Therefore we always
>clear them with pot metabisulfite. Do you really think that this clearing
at which stage?
>is unnecessary and that all dichromate stayed in the STS?
>Best regards, Hans & Chia
Luis Nadeau
awef6t@mi.net
nadeaul@nbnet.nb.ca
Fredericton, New Brunswick, Canada
http://www.micronet.fr/~deriencg/nadeau.html
http://www.primenet.com/~dbarto/lnadeau.html#A0