Re: oil-print-glyoxal??

Ryuji Suzuki wrote:
>
> From: Katharine Thayer <kthayer@pacifier.com>
> 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:
>
> http://web.kyoto-inet.or.jp/people/artbooks/colloP.htm
>

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