U of S | Mailing List Archive | alt-photo-process-l | Re: Gum and Photogravure, was: varnishes

Re: Gum and Photogravure, was: varnishes

16 Kasım 2008, Pazar, 10:11 pm tarihinde, Loris Medici yazmış:
> Perhaps, but in that case what is the fact that makes gum prints as stable
> as carbon prints (you said that earlier in this thread) whereas they
> differ so much in binder? (One gelatin, the other gum arabic.)

Apologies, it seems that I just missed this:
"...I'm comfortable saying that carbon prints and gum prints (both using
permanent pigments of course) shoud be similar in permanence, because
the process by which they are made is similar, and the end product is
crosslinked colloid holding pigment in both cases.  It's possible
that crosslinked gelatin and crosslinked gum arabic are different in
some way that affects permanence, but as far as I know, there are no
data touching on that question, and until that information is
available, I'm comfortable saying that there's no logical reason, or
evidence-based reason, for saying that carbon is more permanent than
gum (or vice versa, for that matter)..."

So, we can't say "carbon is as stable as gum or gum is as stable as
carbon" too, since there isn't any evidence proving that also. In this
case, the only thing that we can say about this issue is "I don't know"...