Re: oil-print-glyoxal??

From: Katharine Thayer ^lt;[email protected]>
Date: 12/27/04-02:08:28 PM Z
Message-id: <>

Ryuji Suzuki wrote:
> From: Katharine Thayer <>
> Subject: Re: oil-print-glyoxal??
> Date: Mon, 27 Dec 2004 15:32:10 +0000
> > I agree with you that very little of this discussion provides a useful
> > answer to Henk's question, which was: what about oil printing, where the
> > point in dichromating and irradiating the gelatin is to create a matrix
> > which functions in such a way that the swollen gelatin repels the oil
> > and the hardened gelatin accepts it. What about the unhardened gelatin
> > that remains in the highlight areas after the print is inked, was his
> > question.
> I didn't quite get his question clearly. Based on what you said above,
> practically the only difference is amount of swelling. That is, amount
> of water absorbed in gelatin matrix is the only difference unless
> unhardened gelatin is purposely washed away.
> But I thought he was more worried about mold/bacteria.

Yes, he was worried about mold/bacteria, but only in the highlights
where the gelatin would not be crosslinked by the dichromate/exposure.
The crucial distinction here, I believe, is not swollen vs not swollen,
but crosslinked vs not crosslinked. Yes, the two conditions overlap to a
considerable extent but they aren't idempotent. For example, when the
water evaporates, the swelling will go away but the gelatin still won't
be crosslinked.

> By the way, if what he is doing is same as colotype (not calotype of
> Talbot), quite detailed instruction is found here:

It's not.
Received on Mon Dec 27 22:04:32 2004

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