Pretty near. In the Woodburytype process, a relief made of *hardened*
gelatin (essentially a carbon print) is (or rather was) used to produce a
lead mold under a pressure of 500 to 600 kg per sq. cm.
There is ample evidence that gelatin has to be hardened in order to last.
Gelatin has to be hardened significantly in order to be usable at all in a
silver system. The only gelatin system that does not use any hardening at
all prior to the image making process is the carbon transfer process, where
heat generated from fingers is sufficient to melt the gelatin tissue in the
unexposed areas.
>Seriously, there is a debate about hardening's ill effects
>on gelatin. My personal view is that making the emulsion
>less flexible could lead to potential trouble, especially
>in environments where temperatures vary a lot but
>humidity is low. I prefer not to use something whose
>effect on my photo is questionable. Ilford's
>current dogma on fixers is never to add hardener if
>doing archival processing, and I believe they do not distribute
The reason for this is that the hardening is done in the manufacturing
process (as detailed in the scientific literature...) Not using an *extra*
hardening at the fixing stage allows quicker fixing and faster washing as
well. It also leaves an image more susceptible to physical damage. It's a
compromise, no matter what you do. BTW, their Galerie paper is a little bit
better from a conservation point of view because of the extra thickness of
gelatin which gives a somewhat superior protection.
Back ca 1976-8, I was one of Ilford's consultants and I met with their
chemists and production people several times at the Rencontres
Internationales de la Photographie in Arles. The paper (later named
Galerie) was manufactured at the Lumi=E8re plant at Lyons.
I must still have 5 or 600 sheets of that stuff around here somewhere.
Luis Nadeau
NADEAUL@NBNET.NB.CA
=46redericton, New Brunswick, Canada
>any hardening fixer in the U.S.
>
>Admittedly I haven't got anything hanging in the Tate or the
>Louvre (yet!), but I have to think of all the money my descendents
>will make when they discover my shoeboxes full of rejects after I'm
>posthumously discovered! Wouldn't want thm to crumble into
>dust, now, would we? ;-)
>
>
>Have a good day!
>Ed Lukacs
>--
>
> _/_/_/_/ _/_/ _/ _/ | Edward M. Lukacs
> _/ _/ _/ _/_/ _/ | eml@gate.net
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