Re: Carbon digest, Vol 1 #107 - 6 msgs

Klaus Pollmeier wrote:

>I found Glyoxal to be as effective and not releasing any fumes (at least I
>couldn't smell them...) but although I washed as usual, the paper yellowed
>after some months until it almost got an orange tone.

I, too, was pleased to discover that glyoxal made an effective replacement
for formaldehyde for hardening gelatin, seemingly without fumes, too, and
then was dismayed to discover the way glyoxal stains the treated paper.
(Incidentally, print staining may be immediately achieved to maximum effect
by placing a glyoxal-treated print in a hot dry mount press.)

Currently, I treat prints hardened with glyoxal in a clearing bath of
Sodium Sulfite and Sodium Bisulfite. To date, prints thus treated have not
yellowed or stained.

Stock Solution:

Water (at 110 degrees F.) 900 ml
Sodium (Meta)Bisulfite 30 gm
Sodium Sulfite 30 gm
Water to make 1000 ml

To make a working solution, dilute stock in cold water at 1:20.

While this solution limits glyoxal's ability to stain the paper, it also
reverses glyoxal's hardening effects on the gelatin, either partially or
completely, depending on gelatin type and paper used. Fresh gelatin
emulsions thus treated may be returned to a soluble state. Occasionally,
over-soaking in this clearing bath will cause the gelatin emulsion to
separate from the paper in bubble-like areas that, once begun, will grow in
size quickly, so I am always careful to limit the length of soak time to
1-2 minutes.

Best,

Tod Gangler
Art & Soul
Seattle, WA.
Received on Wed Oct 18 15:02:14 2000