From: Alan Mynett (a.mynett@ntlworld.com)
Date: 11/09/02-02:27:14 AM Z
Hello David,
Friday, November 8, 2002, 10:14:46 PM, you wrote:
> I don't know the 'James' reference.
> May I bother you for the title?
It's 'The Book of Alternative Photographic Processes' by Christopher
James, published by Delmar. Absolutely indispensable for anyone
(newbie, oldbie, whatever..) interested in alt photo. James describes
the process using gum arabic (which is a plant carbohydrate resin), but Alt uses
gelatin (an animal protein).
Very briefly: a gelatin layer containing potassium dichromate (and
possibly - Alt doesn't say - a sticky substance like honey) is coated
on a support (paper etc) and exposed to UV (sun) light through a positive
transparency in contact.
Where the light falls (highlights in the positive)the gelatin mix hardens.
Where it doesn't (shadows), the gelatin remains sticky. The matrix is then humidified
and 'dusted' with dry pigment (exactly how Alt does this I don't know).
Because of the honey, the remaining gelatin is 'tacky' and holds the
pigment, much more in the shadows than in the highlights.
Lots of control is possible at the dusting on stage.
I understand (from what the gallery owner said) that Alt then fixes his
image by careful heating to *very* slightly melt the surface of the gelatin
and so lock in the pigment.
Best wishes
Alan
www.mynett.org.uk
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