Re: Hardening gelatin

Katharine Thayer wrote:
>
> Ryuji Suzuki wrote:
> >

> >
> > One major difference between gelatin and gum is that unhardened gum is
> > very soluble even in cold water, whereas unhardened but gelled gelatin
> > is insoluble in cold water. In dichromated gelatin process, the
> > exposed material must be washed by water that is hot enough to
> > dissolve away the unexposed gelatin while retaining exposed gelatin
> > and sizing material.
> >
>
> Ah, this is an excellent point, and well taken. Had I put a lot of
> energy into thinking that I was hardening my size while I was hardening
> my image, I'd feel a bit foolish at this point. But since I haven't, and
> in fact 99% of my work has been done with no additional size, I don't.
> But what you say makes sense.

Actually, I thought about this a little more and decided I'm not so
enamored of the argument as I thought I was. I already said that the
overall hardening of the size wouldn't work with an image that had a lot
of white in it, so that goes without saying. When I was sizing and not
hardening the size, I was doing tricolors that had tone throughout; at
least one of the three negatives provided some exposure at every place
in the image. There just weren't paper-white areas in those images to
speak of. So the gelatin should have been hardened throughout the image
area (as well as outside the image area, since I don't mask off the
borders).

So, sure, if you were going to print an image that had a lot of white in
it, and if you used unhardened gelatin as a size and you didn't
subsequently put the print in hot water to eliminate the unhardened
gelatin in areas that didn't get exposure, then you'd be left with
unhardened gelatin that might potentially compromise the longevity of
the print in some way; I can see that. But certainly for the images I
personally printed on unhardened gelatin, that wouldn't have been an
issue; the gum printing process should have hardened the gelatin
sufficiently throughout, I think. True, I'm just assuming that, but
since we still haven't come up with a way to demonstrate definitively
whether the gelatin is hardened or not, how would we know?

Not sizing at all seems to me to eliminate a lot of potential headaches
from the get-go; I'm glad I stopped sizing a long time ago.
kt
Received on Tue Mar 30 21:13:00 2004