From: Judy Seigel (jseigel@panix.com)
Date: 12/16/02-05:09:16 PM Z
On Mon, 16 Dec 2002, Tom Ferguson wrote:>
> I "think" the glyoxal yellowing is based on exposure to UV or light. I
> use to store treated paper in a shelf under my "built in" UV bank. The
> edges of the paper (particularly the top sheet) that aligned with the
> front of the UV bank would yellow. The rest of the paper (shaded from
> the UV) would not yellow.
>
> I don't store my treated paper there anymore ;-)
Tom, I tried to bleach OR induce the stain by exposing the paper directly
on UV light table for an hour and a half -- no change. I think the
original speculation (whose was it?) that it's air AND light, may be it,
or anyway close.
> I found that washing/developing the paper removed "most" of the stain. I
> don't think I wash as long as Judy often does.
For whatever reason, maybe my airless premises, or pollution in NY, or
whatever, this is a problem I have rarely had, and then mostly appears on
edges, along the line of gelatin build up. In the course of making a
print, it always disappeared... with my usual soaks, which as a rule
average an hour, or less, but could be overnight.
However a plain water soak did remove it (and I have the sample to
illustrate), and again, given the givens i consider the "problem" trivial.
I'd guess that if Kerik's didn't disappear, it's --- who knows what?
Since mine occurred along the line of gelatin buildup, I'd speculate that
he may have used more -- or harder -- gelatin than I do. Or perhaps from a
more stain-prone source. I did some other tests, applying dichromate coat
over the stain, don't recall the finding however -- that was a year or 2
ago. I'm trying to remember last week.
As I've said before in these pages, I found fresh paper took more pigment
stain from the formaldehyde-hardened paper (& have the test strips on
that), also the outgassing after an entire day of drying outdoors was so
strong & burnt throat & eyes so miserably, I had to remove the
formaldehyded paper from the studio. Glyoxal I can even use indoors.
Perhaps when it was finished outgassing the formaldehyded paper was
better, or.... as we know, gum is very variable according to what, who &
where.
J.
>
> On Sunday, December 15, 2002, at 09:57 PM, Kerik Kouklis wrote:
>
> >
> >> but whatever yellow occurs will disappear with a long soak in water
> >
> > 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
> >
> >
> >
> --------------
> Tom Ferguson
> http://www.ferguson-photo-design.com
>
>
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