Re: Hardening gelatin (Ws: glutaraldehyde)

On reflection I find that I am not as persuaded by Judy's argument here
as I thought I was. I was trying to be agreeable, but actually my
suggestion isn't so tremendously theoretical. I know from experience
that I can pour boiling water over my prints with no ill effect; I know
from experience that I can soak my prints in boiling water with no ill
effect, because I did both of these things recently to demonstrate the
tenacity of properly hardened gum for my page in progress on the
chemistry of the gum process. It's certainly reasonable, given the
melting point of gelatin, to suppose that boiling water would melt any
unhardened gelatin in the paper. So I don't think this is such a
cockamame idea at all.

I backed off because I realized that not all gum printers print in such
a way as to actually harden their gum, and of course this wouldn't work
on unhardened gum, which dissolves much more easily than unhardened
gelatin. I personally don't understand why anyone would print in such as
way as to not harden the gum well, given how ferociously soluble
unhardened gum is, but as I always say, "each to his own."
Katharine Thayer

 
Judy Seigel wrote:

        Katharine Thayer wrote:
>

> >
> > > ....If there are large areas of white in the
> > > image, you should either harden the gelatin before printing, or soak the
> > > print in hot water after printing to remove the areas of unhardened
> > > gelatin that weren't hardened during printing due to lack of exposure.
> >
> > I would not advise that, at least not without careful testing... First,
> > to get the water hot enough to melt off gelatin without any agitation --
> > just melt it off the paper, especially when it may have had *some* tanning
> > -- is not a sure thing. Secondly, that could well soften your image,
> > which if you've used low dichromate and minimal exposure could be soft and
> > susceptible, and melt some of that off as well. But the idea seems highly
> > theoretical, at least until proved by testing (tho how you test to see
> > that the gelatin is off I don't know). And even if it "worked," sounds
> > like more trouble than hardening.
>
> Here I have to agree with you; that was a half-baked idea that had no
> basis in experience. I don't know what came over me; I don't usually
> talk off my elbow like that. I guess I was just trying to think of a way
> around hardening, because I'm kind of down on hardening at the moment
> and wanted to give people an alternative. But I agree, it wasn't a
> well-thought idea. I'm pretty sure it would work for my method, because
> when I'm done my gum is well hardened; you can pour boiling water over
> one of my finished gum prints (I tried it a couple of weeks ago for an
> illustration for my website) without affecting it in the least. But I
> am aware that not everyone prints the way I do.
> Katharine
Received on Fri Apr 2 06:26:53 2004