As for alum in gum size, I, too, have read warnings against it in RECENT
books. But just about every pictorialist/early-gum how-to I've come
across, if it added gelatine size, called for alum to harden it. (Puyo
decisively dismissed the need for added size, though he's the only early
source I think of who actually mentioned formaldehyde in case you did size
-- that is, he called for "formol", which is NOT in my French dictionary,
but I take it for formaldehyde.) The alum, BTW, was usually added to the
gelatine, not used as a separate bath. Are those prints OK? The early
gums I saw were, but were they alummed??
On Tue, 25 Jul 1995, Dan Shapiro wrote:
> If the point of sizing is to make paper fibers resistant to staining and
> expansion/shrinkage with water, could you, in principle, size paper
> using dichromated gelatine, exposed without a negative?
That's pretty ingenious, though it might stain, or would take a long
soak to remove the stain, and, if the purpose is to
avoid noxious formaldehyde, how much improvement would extra dichromate be?
Why don't you try it, though?
Incidentally, the pictorialists were wont to expose a coat of just gum and
dichromate without pigment (or only a tiny amount) to give an allover
tone to the paper.
> My intuition is telling me that quality/predictability will be enhanced
> if we can reduce the number of chemical agents involved in making gum
> prints.>
Maybe, maybe not. The gelatine in dichromate would be different from the
gum in dichromate.
You're an optimist, though, thinking you can outwit "it."
Judy