Re: Glyoxal?

Katharine said:
Chris is the only one I know of who has
> reported that rinsing doesn't eliminate the yellowing, although she
> reports knowing of others.

Maybe Kerik, Clay, and Sandy will carry more credibility than I...
messages cut and pasted below.
anyone who wants my gloxal yellowing squares sent as a jpeg offlist (til my
website goes up) I'll do so. End of discussion for me.
chris

No, that is not necessarily true. In fact, once the yellowing of the glyoxal
has occured, I have not been able to remove it at all (long soaks,
metabisulfite, hypoclear, acid baths, 80 grit sandpaper, jackhammer...)

I find if I print on the glyoxal-hardened paper before the yellowing has
occured, then it doesn't happen. Once the yellow is there, it's there for
good. (I am mostly using Fabriano Uno and Whatman's printmaking paper;
glyoxal mixed in w/the sizing in one step.)

> In any event, I wouldn't return to formaldehyde including because it
> stains more than glyoxal (in my tests).

Are you talking pigment stain or this yellowing effect? If you mean pigment
stain (and I think you do) I would completely disagree. If anything, in my
tests, formaldehyde hardens more than glyoxal (ie less tendency to stain),
although I have no problems with staining with either hardener.

Kerik

It may be that UV light causes yellowing with glyoxal, but I have
seen it also with papers that were not exposed to any UV light so
there more going on here that just the UV light.

Regardless, I don't have time in my life for papers that yellow, and
that may or may not clear in the future depending on treatment, so I
will not use glyoxal again.

On the other hand, I will also never use formaldehyde indoors again
-- never. The fumes are just to obnoxious when used with my method of
sizing paper.

So what to do? It is chrome alum for me. No fumes and hardens as well
as formaldehyde, though not quite as fast.

Sandy King

Well, last weekend, I sized five prints that I had every intention of
throwing the gum on in the next couple of days. Yeah, I know, five
prints. I always super-size it. As could be predicted, real life
intervened and I didn't get to them until today (Friday). The five
prints had been in a stack in my darkroom, and the sizing on the one on
top had already begun yellowing! Strangely, the ones beneath it were
fine. So what I learned was: 1) size paper with glyoxal hardener pretty
close to its actual anticipated use and 2) there must be some effect
that unrestricted air circulation above the face of print accelerates
the yellowing process.

Two cents worth.

Clay
Received on Tue Jan 17 21:01:53 2006