From: "Elmer L. Fairbank" <elf1@cornell.edu> Date: Mon, 30 Sep 1996
> >#3 In Kent Wade's "Alternative Photographic Processes", Morgan & Morgan
> >1978, ISBN 0-87100-136-5, p 77 - 78 he mentions two methods one
> >non-silver technique using a colloid made of gelatin, water & sugar
> >sensitized w/ammonium dichromte (no recipe)
> there is an exquisitely beautiful colour portrait by
> Garo on a ceramic tile at the George Eastman House. I don't know the
> technique he used but I'm sure they might. Gum Bichromate was his usual
> method, but in this case, I just don't know.
There are (at least) two main types of (classical) multicolor photoceramics
processes. The "true" (burning out) and the "imitated" (usually a
multilayer pigment print on ceramics as a final transfer material).
The steps of the (classical) "true" process:
--------------------------------------------
1. To make a positive on a transparent material i.e. glass plate, film. etc.
2. To make the sensitive layer: usually gum, sugar, bichromat and additionals
on any useful base material.
3. Exposition (contact).
4. Developing by water treatment. The result: a surface with several levels
of sticking ability up to the exposition (the highlights wich are exposed
by light don't stick at all, the shadows are sticking because the normal
gum with water is sticking and the halftones are between, up to the
hardening level of the layer).
5. Blowing or brushing by extremely fine powder which is create the
density where it is sticking to the mentioned gum layer.
6. When the picture is visible/ready it will covered by a collodion layer
and because this material (after drying) can catch the powder stronger
than the gum, the picture will be removable by the collodion layer.
7. To place and fix the powder/collodion picture layer to/on the ceramics
and burning out.
I have a few receipts about the color-version of the "true" also, but I
think (I cannot to try it -- till now) it is extremely difficult. It
working by (usually) fine powder of several metallic oxides (as a pigment)
because to get an enough good color rendition nearly impossible. (These
colorants surviving the burning process -- opposite of other pigments --
but the possible colors of these materials are not the best for a good
quality color photograph.)
So my tip (if the picture is beautiful): pigment multilayer/color.
- Balint Flesch -