Re: gum "stain" with zero exposure... etc.
On Wed, 7 Oct 2009, Tomas Sobota wrote:
Admittedly Tom, parts of my memory have been eaten by worms... and 2 to 3 years ago I didn't have the browser I have now so wouldn't have seen your example... HOWEVER, to a non-chemist/ trial & error "scientist," I'm not sure that working on glass rather than paper couldn't have the same explanation (or "explanation"). After all, if the emulsion hardens enough to keep the pigment in place, but not all of it hardens, there would still have to be gradations between viscous, slightly viscous and free dissolving..... No?????Two, three years ago, during a loooong thread on this inversion effect, I posted on the list that I observed this effect with gum on glass. I posted some pictures, even. So, the explanation by Mike Ware, with all respects due to him, is not enough for me. Also, the method of hardening is irrelevant in this case, since glass does not need any hardened gelatin coat. I used depolished glass. Tom Sobota Madrid, Spain