From: Judy Seigel (jseigel@panix.com)
Date: 02/28/03-09:03:16 PM Z
On Fri, 28 Feb 2003, Christina Z. Anderson wrote:
> me, scientists: I thought we could paint straight glyoxal on a scrap of
> paper in a swath, and then add a bit of sodium carbonate to some glyoxal and
> paint a strip of that next to the previous. Then see if there is an
> appreciable yellowing going on. Next, you could REALLY rinse out the paper
> as best as possible, or use an acid neutral paper, or even acidify a piece
> of paper by soaking it in vinegar, and perform the same test. Somehow, I
> know there is a way to test this alkaline/glyoxal possibility of staining.
> We could take both tests and keep them in the dark, and both and put them in
> the sun. Any takers? I do feel the glyoxal yellowing is something important
> to test, even though there are so many variables. If the yellowing is
> greater where there is more concentrated gelatin at the edge of the paper,
> that does not disprove this possibility, but strengthens it. First of all,
> more gelatin, more glyoxal in there (if glyoxal is not done in a separate
> step). Second of all, more gelatin, less light passes thru, more stain is
> noticeable.
Chris, none of these seem applicable... the glyoxal is a later coat, not
in the gelatin, the tone is different from the tone of the alkali'd
glyoxal, the tan look of the sized paper takes weeks to appear... and so
forth.
J.
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