Still, there ought to be substitutes...
Anything precious for example, ground to powder. Your wallet. The hood
ornament from your treasured '67 volkswagen bug. Leftovers from a meal
you paticularly enjoyed. The operant principle is stickiness here.. the
difference in texture between exposed and unexposed colloid, so there
are fewer demands on the coloring agent. It needn't be quite so
excessively ground up, I think, and capable of going into suspension in
the colloid (in comparison with pigments for gum prints).
By "collodion" I expect they mean gelatine? Will the whole thing really
get hard enough to lift off of the (glass) substrate and transfer
elsewhere? Any complications in doing this on a paper substrate.
I can hardly wait.
Judy - thank you!
Dan Shapiro