Re: oil-print-glyoxal??

From: Katharine Thayer ^lt;[email protected]>
Date: 12/25/04-07:07:23 AM Z
Message-id: <>

henk thijs wrote:

> HI Katherine,
> Thanks for the answer; I use different watercolor 300grs for the
> oil-process (apart from old silver-gelatine papers after a bath in
> plain hypo, the easiest way to get an oil-paper).
> But the next question would be: why the hardening by gum-prints after
> sizing with gelatine. Isn't the purpose for this treatmentn also not
> to prevent mold-growth?

My comment about paper manufacturers not hardening their size probably
wasn't overly useful to the discussion, since it begs the question of
doing something to retard mold growth; I just thought it was an
interesting thing to throw into the mix. It wasn't actually intended as
an answer to your original question, which I still think was a good
question, but just as another bit of information to consider.

But I'm not sure I understand this part of your comment, "The next
question would be: why the hardening by gum-prints after sizing by
gelatin. Isn't the purpose for this treatment also not to prevent

If you're asking why harden the gelatin by printing gum over it, I would
say the purpose of hardening by gum prints is to make gum prints; the
incidental hardening of the underlying size, and consequent prevention
of mold growth in the underlying size, is an added bonus. Whether it
hardens the gelatin clear through in areas of light tone is an open
question of course that I don't have an answer to.

If you're asking the more general question, whether the purpose of
hardening a gelatin size isn't to prevent mold growth, that's what I
always thought the purpose of hardening gelatin was, but I'm told by
other gum printers (see Kate's comment) that they harden the size
because unhardened size doesn't prevent pigment stain for them. Since I
don't have a problem with pigment stain, with either unsized paper,
unhardened size, or hardened size (except for a couple of papers that
are inherently prone to speckling, like Arches) I can't add anything to
that part of the discussion.
Received on Sat Dec 25 15:03:22 2004

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