U of S | Mailing List Archive | alt-photo-process-l | Re: glyoxal v. formaldehyde

Re: glyoxal v. formaldehyde

On Tue, 8 Apr 2008, Don Sweet wrote:

Yes Judy, but my 2nd question is based on the notion that when it has
finished outgassing it is all gone.  By contrast, something that doesn't so
readily outgas presumably remains in the size to continue doing its toxic
work (unless perhaps the act of hardening the size neutralises it in some

I admit I don't follow this. My surmise is that linked is linked whatever the residual solution smells like.

Observation also suggests that the job is done when it's done. You can put a formaldehyde-hardened print in water as soon as the gelatin is dry & soak it overnight,-- or even 24 hours (which Paul Anderson bragged about) -- and it's still hardened. My tests with glyoxal showed that after a certain length of time (like 5 minutes or less) you could wash the print and the gelatin remains hardened.

But formaldehyde was hardener of choice for circa 100 years... there didn't seem to be a problem with it coming undone -- if that's what you mean (?) IME, it's at least as permanent for hardening as the others.

What you didn't mention however is that allegedly glyoxal is nearly as toxic as formaldehyde, but we don't notice it because we don't smell it. I have no idea if this is true... but again our time with it is, relatively speaking, brief, and the cars outside my window are gunning their motors 24/7...