Re: report on glyoxal yellowing

On Mon, 15 Nov 2004, Christina Z. Anderson wrote:
> There is disagreement whether, once the yellowing occurs, it is removable
> with a soak. Judy says yes. Kerik says no. I think my answer is no, but
> I'll soak my measely little strips and tell you.

It was a long soak.

> For those of you long term listies (I've only been on since 99), who
> instituted the use of glyoxal for hardening in alt process? Luis Nadeau says
> this below. Dick Sullivan, do you know? I've cut and pasted this.

For better or worse, I believe I was the agent of glyoxal on the list --
but by way of Mike Ware. I don't remember the year, but possibly about
1996, Mike Ware was still on the list and interested in various issues of
gum bichromate -- although at the time he hadn't done it himself. But it
seems he had supervised a graduate student (whose name I may even have
somewhere) on the use of glyoxal instead of formaldehyde in hardening
gelatin... Then the graduate student went off, as Mike put it "to the
Antipodes" (I had to look that up to confirm that it meant somewhere
around Australia), without publishing his findings. (Also, as I recall,
this discussion was offlist.)

It was about then that formaldehyde was being kept off the general market
(ostensibly because of toxicity, but by informed unofficial consensus
because of its use in making crack or similar -- I'd been hearing from
hospital personnel how it disappeared from locked cabinets). Facing
problems of using formaldehyde in class (I could get it through the
school, but its use with undergraduates was always problematic), I decided
to test glyoxal -- obtaining some at that time through the chemistry dept.

My tests showed that it hardened *better* than formaldehyde, in that day-
old strips showed *less* staining and steps were equal if not better.
Equally important, although the test papers had been TOTALLY dried
outdoors, when I took them indoors, the formaldehyde papers still
outgassed with fumes strong enough to burn my eyes and throat until I
removed them from the room. (I know enough now to wonder if a week later
the strips would have worked equally well, or.... not. But that was then.)

I hadn't yet seen the problems of storing the working solution (which I
consider minor -- don't bother using it past the 2nd day) or yellowing,
which may be minor or major according to ones own variables ... now under
discussion.

In any event, I reported the initial findings to the list, and probably
set off the practice... various other considerations arrived later, from
various sources, and are still in consideration.

Judy
Received on Mon Nov 15 13:24:00 2004