From: Sandy King (sanking@clemson.edu)
Date: 12/16/02-05:02:29 PM Z
Tom Ferguson wrote:
>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).
>>
>>
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
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