From: Judy Seigel (jseigel@panix.com)
Date: 12/06/01-01:43:35 PM Z
On Thu, 6 Dec 2001, Ted Edkins wrote:
> The compound is potassium chromium sulphate and is often sold as the
> dihydrate.
> According to Scopick's book The Gum Bichromate Book the compound is a
> better hardener than potassium alum ie potassium aluminium sulphate but
> dosen't keep as well.
Before taking any such assertion in Scopick at face value, I would retest.
He is quite fallible, often disastrously so. His source for that claim may
be correct (and it's been the consensus on this list that chrome alum is
best) but I'd bet a nickle he didn't test it himself. (Actually, I rarely
bet less than a million dollars, but somehow a nickle seems more polite.)
In my experience, BTW, cut-and-paste text is safe for silver gelatin,
because the ur source of the information is either Kodak or by way of
Kodak.
For alternative processes you're on your own -- the classic "sources' are
full of error... from *their* "classic sources." (That's why this list is
so great & essential. There's usually someone who knows.)
Judy
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