Re: Gelatin hardening question

On Thu, 15 Jul 2004, Christina Z. Anderson wrote:

> Chrome alum was always the hardener, AND clearing agent, mentioned
> "back in the day".

I have seen several references to "formalin" in early 20th century
literature, one might even have been Demachy.

> I am placing an order to a chemical company soon, and thought I would
> order some formaldehyde and give it a try. Sarah Van Keuren is positive
> about formaldehyde use. I had a stack of formaldehyde hardened paper that
> someone gave me years ago that worked great, but Judy's experience with
> outgassing has scared me, too,

For maybe 10 years at Pratt we hardened gelatin with formaldehyde,in
classes full of, as I may have mentioned, space cadet undergraduates.
But we did it outdoors... in a very structured way. The students lined
up, put their paper in the tray, turned it over, and hung it on
clotheslines in the October breeze -- where it waved until totally dry,
then was stacked (by me -- the class was over) in the empty lab which had
some ventilation (of sorts) in the ceiling. The students collected their
own sheets whenever (usually 2 or 3) and put them wherever.

In other words, no wet formaldehyde came indoors. The dry papers were
dispersed.

But there were times I had to harden my OWN paper at home. It was
tolerable, although unpleasant, when done outdoors. However one dark
night when I couldn't work outdoors I tried it indoors, in the hall, with
doors open for cross ventilation and a fan. It was ghastly. That is, no
after effects I could say for sure, but eyes nose and throat burned and
watered. I hung the batch in the same hall to dry-- it probably outgassed,
but the stench was already so great, who could tell.

The last time I used formaldehyde I was testing it against the then new,
amazing glyoxal, handling both identically, both outdoors on a summer day.
I hung the sheets outdoors, bringing both in after a couple of hours, when
both were bone dry to the touch, and stacked them in the studio, which has
high ceilings, but not much ventilation otherwise.

There was soon a very distinct and irritating formaldehyde odor
("outgassing"), but none from the glyoxal. Since my 21-step tests at that
time showed that the glyoxal-hardened paper gave cleaner whites, & the
glyoxal had only the faintest odor, much milder than the acrid biting
formaldehyde, I switched to glyoxal.

Even at the time it occurred to me that maybe the formaldehyded paper was
"too fresh," that it might have performed better a day or more later.
But since the glyoxal was at least as good, and no problem to use, that
was beside the point.

As far as I know, however, there is no evidence that either one of them --
IN THE QUANTITIES AND FOR THE RELATIVELY BRIEF TIMES that we use them --
are harmful. Those hazards sheets are for INDUSTRIAL STRENGTH IMMERSION
40 HOURS A WEEK. If you check gum arabic you'll be afraid to use it too.

Of course there can be harm we don't directly see in any concentration,
but considering all the pollutants, poisons, allergens, contaminants and
whatnot that surround us EVERY DAY, I think fear of, for instance, glyoxal
is -- I was going to say "verging on phobia," but realizing that that
might raise a few eyebrows, or hackles, I'll just say -- "excessive."

> ... as well as glyoxal's yellowing problem.
> Maybe we can get around glyoxal's yellowing by rinsing the paper, but how
> about in 50 years?

I haven't heard of or seen paper that had not yellowed by the time it was
printed getting yellow later. And my own experience was that long soak
cleared it when it had occurred. Not that we know enough about the process
to say it's NOT POSSIBLE, but the current collective experience suggests
that rinsing, or the long soak of printing, prevent that. (But ask me in
50 years !)

>... I've heard that both glyoxal and formaldehyde aren't
> very good for you, so my bottom line is, it all sucks.

Anything that's not printing or photographing sucks, & even they suck at
times....

Judy
Received on Thu Jul 15 23:15:00 2004