From: Judy Seigel (jseigel@panix.com)
Date: 03/08/03-10:27:12 PM Z
On Sun, 9 Mar 2003, Liam Lawless wrote:
> Hi Folks,
>
> I'm no gum printer, but does gum arabic maybe have a shelf life, after which
> it hardens "spontaneously" after drying out (i.e. after coating)? And is
> contamination with glyoxal or similar too far-fetched to consider?
some of my favorite gum arabics are 10 or even more years old... the
color may darken (oxidizing) but I don't see any change in effect.
Meanwhile, I, too, find the ratio of black powder to gum Ed cites amazing
-- it's hared to figure how it could even have been liquid enough to
spread. But you can't compare it to chris's paint in a tube either. The
tube paint contains heavy moisture, gum arabic, extenders, thickeners,
fillers, whatever -- so six grams of tube paint could have, say, 1 gram of
pigment. Maybe someone misplaced a decimal point?
J.
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