On Wed, 22 Dec 2004, Joe Smigiel wrote:
>.... I've not read about this additional hardening effect in
> the standard texts on gum nor do I recall the topic of chromium
> hardening of gelatin being discussed on this list.
When Terry King was on the list, he advocated a light exposure to a layer
of gum arabic (or he may have used ossein or gloy) as first size. Several
of us tried it, and we did run a thread (tho I don't recall the subject
line). I don't recall any great epiphanies, and I was among those who
found several problems, and no improvement over regular hardened gelatine:
I found the sizing effect not as good, and the residual dichromate stain
impossible to remove completely.
Which is not to say that different combos would necessarily have the same
problems, but my feeling at the time was, if it's not broke, why dink
around? (Tho, on 2nd thought, it may have been intended as a way to avoid
using formaldehyde.)
I think it was Peter Fredrick (tho possibly Peter Marshall?) who
described weak sulfuric acid (3%?) to remove the stain -- it did work,
within limits, but was slow, tedious and a dubious "help" to the paper,
and still left a tan coloration.
Judy
Received on Wed Dec 22 13:41:33 2004
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