From: Jean Burdett (jburdett@chariot.net.au)
Date: 12/31/00-11:19:29 PM Z
Thanks to Rod Fleming and other folk for responding.As Rod confirmed, gum arabic will harden on its own upon exposure to u.v. light,even if less rapidly and efficiently as gum with dichromate. Therefore the print I produced with instant coffee is no great mystery. The parts of the canvas exposed to light were brown,and the unexposed areas remained white. I will try stonger coffee. I will also try exposing the the canvas a multiple of times so that the brown areas may become darker. It was interesting that Rod noted that this method would be suitable for children. I was initially interested in finding a technique accessable to everyone, including children, people with intellectual disabilities and mental illness, hence my concern that all chemicals should be non toxic when eaten. The difficulty with this, and other potential methods,such as anthotypes is that it takes so long. This would be a problem for people with short attention spans,or short term memory. It could also raise logistical problems in a workshop context.
I still don't know whats going on with the Prussian Blue. The pigment was not drawn into the canvas. The image I produced was visable only before developing (or in this case destroying) in water. It was a positive image. The exposed areas were lighter than the unexposed areas, suggesting some ssort of fading had taken place. Windsor and Newton Prussian Blue is meant to be reasonably light fast, according to www.handprint.com (3.5 out of 5). However it can fade when in contact with an alkaline substance. Is gum arabic alkaline? I can't think of any better explanation at this point. I am testing to see if
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