Re: glyoxal v. formaldehyde
From: "Christina Z. Anderson" <email@example.com>
Subject: Re: glyoxal v. formaldehyde
Date: Tue, 08 Apr 2008 08:24:19 -0600
> Thus, when buying the Photographer's Formulary glut you
> would need 0.6ml to 2.4ml of the 25%; when buying Maxicide
> from a medical supply warehouse which is a 2.5% solution,
> you would need 6ml to 24ml of this to your liter of gelatin
> made up as a 3%. I usually use 6-10ml of the 2.5% per
> liter. 30 ml which I tried one time was absolute overkill.
Wow. Do they sell 25% stock of glut?
I handle 25% stock myself, but only in fume hood, and only
after sleeping 8 hours and drinking my coffee from Yemen or
> Two, the reason glut is so effective, aside from the fact it
> does not outgas (it does have an acrid smell when I first
> dump it in the thermos of hot gelatin) is the smoothness it
> produces. Both formaldehyde and glyoxal make the
> gelatin....feel rough. Glut is smooth. Now, I am not a
> chemist and have no idea why this is so and can only
> describe it in layman's terms, but it feels like a bandaid.
I agree. A glut molecule has two sites that can bind with
gelatin to crosslink two gelatin molecules, and the distance
between those two sites (counted by the number of carbon atoms
between them) is very close to ideal. This contribute to the
efficient, fast reaction of high yield, and also better
control of gelatin swelling (not too much, not too little).
Some other hardeners can have the same property, and in fact
those vinylsulfone hardeners have the same property and they
are widely used, but the compounds themselves are probably
synthesized by the photographic film/paper manufacturers or
their group companies and not generally available.
> I would be the last one to propose using toxic chemicals,
> but we are already doing so. Dichromates, formaldehyde,
> glyoxal, might even throw in prescription meds in there.
> Apparently this era is nicknamed the prescription med era
> and there was some news program talking about all those meds
> in our water supply!!!! All those meds messing with our
> brain chemistry scares the heck out of me. I'll stick to
Again I agree. I have removed all harmful compounds that can
be substituted with safer alternatives without losing
performance in my silver gelatin processing solution, and I've
also considered energy needed to synthesize ingredients,
etc... I also want to optimize the bottle packaging and all
possible areas to minimize health risk and environmental
impacts. HOWEVER, for those who are committed to hand made
photographic prints, I think glut toxicity is a relatively
small problem that brings a huge advantage. I wouldn't rate
glut "safe" in the general consumer standard, but compared to
its alternatives (that are available commercially), I'd say
it's safer and better.
I said this several times before, but ALL hardeners are
dangerous, because they can crosslink protein molecules in the
skin, in the eye, etc., just like they crosslink gelatin. I
wouldn't waste my time seeking a completely innocuous
Glut keeps for a long time as long as it is kept in an acidic
solution (pH of about 4 is good), in a tightly closed
container, in a cool, dark place. Not as air-sensitive as
developers or formaldehyde or glyoxal, but I'd still avoid
> However, don't med students get exposed to formaldehyde all
> day long with cadavers?
Cadavers are fixed with a fixative (which probably blends
formaldehyde and glutaraldehyde, among other things, such as
some dyes) but the solution in the sprays used to wet the body
in everyday dissection is probably just biocides (they can be
phenol, thymol or similar componds) and surfactants. The spray
I've used smells just like Chloraseptic spray (oral anesthetic
spray for sore throat) which contains phenol. By the way, that
type of spray doesn't really work well for sore throat beyond
5 seconds, besides, phenol is not something I want to put in
my mouth (or the drain). (But at the same time there's nothing
really effective you can do to take care of bad sore
"The truth that I am seeking is in your missing file."
(Bob Dylan, Something's Burning Baby, 1985)