From: Tom Ferguson (tomf2468@pipeline.com)
Date: 12/16/02-08:50:23 AM Z
Entirely based on non tested observation:
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 ;-)
I found that washing/developing the paper removed "most" of the stain. I
don't think I wash as long as Judy often does.
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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