RE: Glyoxal?

Judy and all,

My BFK hardened with Glyoxal never did yellow under any condition. That is
exposed to window light indoors, exposed to light (but kept dry) outdoors
and stored in complete darkness in and out of a sealed plastic bag.

The paper was exposed to light for months and the same length of time for
the dark storage samples.

I did rinse with tap water after the tray sizing. The Glyoxal was mixed with
the gelatin using the proportions recommended by Christopher James.

Don Bryant

-----Original Message-----
From: Judy Seigel [mailto:jseigel@panix.com]
Sent: Monday, January 16, 2006 9:11 PM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Glyoxal?

On Mon, 16 Jan 2006, Christina Z. Anderson wrote:
> Your tests prove that glyoxal does yellow, but not always. My tests prove

> that glyoxal does yellow, too, but in degrees. I would therefore hope
that
> our tests that we have spent so much time on are worthwhile to ourselves
> personally and to others on this list. How else would we develop a
database

(etc.)

Before we abandon the principle of cause & effect, a suggestion:

I found that every alkali I tested turned glyoxal yellow or orange sooner
or later, very or somewhat. And we know that MOST (if not all)
contemporary art papers are buffered, that is, stoked with alkali to
counter the acid effects of air, or rain, or water, or more probably the
nasty chemicals used in making the paper or the water the factory uses.

So it could be the paper buffering that causes the yellowing. Why don't
all art papers yellow all the time in glyoxal? Possibly the water supply.
Most of us use tapwater from different sources -- so they're different.
There's also the "pump house" where civil servants add different
ingredients according to season and weather, needs of the moment &
theories of the state legislature.... So our summer water may be different
from our winter water, etc. etc. etc.

Should a day come when I have time for more tests, I'd use the pH pen to
test pH of paper, and then test pH of the water. We do know that some
water sources are very alkaline (they can bleach your cyano overnight).
That might also yellow your unrinsed glyoxal paper. But some water might
be relatively acid, & counter that tendency of glyoxal. I'd also test tap
water for development versus distilled for both mixing and developing...
which might also shed light. Or dark.

Plus art papers vary batch to batch & by the season they're made -- I'm
told that's because the water they're processed in changes... Friend told
me some of his paper customers only buy paper (for platinum) made in, I
think it was winter, but we don't know when the paper we buy from Sam's
art store, or online, or find in a drawer was made.

The only trouble with this theory of course is that some of us watching
this have found our STUDIO is consistent, even as the seasons change. I
have no theory for that.

Judy
Received on Mon Jan 16 20:47:35 2006