Re: Hardening gelatin (Ws: glutaraldehyde)

On Thu, 1 Apr 2004, Katharine Thayer wrote:

> Interesting how different our observations are, as I found Arches
> printed without pigment stain, either unsized or sized with unhardened
> gelatin. Which just goes to show how little use our personal

It occurs to be that we may be talking about different "Arches". This was
quite a few years ago, and may have been "Arches cover."

> .... Stop reading this junk
> and just go make gum prints; you'll learn all you need to learn from the
> doing of it, and what you learn will probably be entirely different from
> anything you read here.

I would think it's helpful to know the options; in fact I suspect this
discussion is more helpful to beginners than any of the books, which
rarely indicate the variables. Tho I have one from 1901 and one from 1937
that do say you can do just about anything & don't bother with my rules --
but they both go on to give some parameters.

> Here's what I think: if you can learn to print without sizing, that's
> the best way to go.

I'm not sure it's a matter of "learning to print" without sizing... I
think it's finding the print you want to make, which may not be made
without size. In my experience the look and effects are different.

> then the size should probably be hardened one way or another. The
> hardening is not to keep the gelatin from melting during gum
> development;

I never heard of gelatin "melting" during development, at least not normal
tap water development. I doubt that happens. In my experience, sized
paper gives crisper tones, better separation -- as shown repeatedly in my
comparison 21-step tests. That that may not be the "look" you want, is of
course possible. But IME it's different. Then again a first coat of cyano,
etc. etc. also make the look different.

> ....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.

Judy
Received on Thu Apr 1 21:02:36 2004