Re: glyoxal v. formaldehyde
If you used glut, you would only need
about 0.5 to a a couple of percents glut (in relation to the gelatin content, not water). Ryuji Suzuki
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.
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 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 coffee.
Thanks, Ryuji, for saying we should mix it immediately into a 2.5%. Hey, does it ever go bad?
In answer to your question, Ryuji, I put Mike on the spot one day with the last go around about glut because I was really struggling about teaching it in my alt class, and he graciously gave me answers from his hazard text that I was looking for. That last email was a paste of two posts, his first, yours second. I apologize if that was not clear enough.
One last thing about toxicity. I think a while ago I told you all I was banned from teaching mordancage at my university because it released toxic chlorine gas potentially. I called the former head of Risk and Safety who now has some bigwig job with insurance companies (some kind man gave me his cell phone number) and he 100% said that the way it was mixed and the dilutions used there was no risk. But now I have to teach it at my house outside every fall with a disclaimer signed by the students, and voluntary attendance. But I suppose if one poured straight hydrogen peroxide on top of copper chloride which certainly COULD happen with a student, this was the concern, so operator error is always a scary possibility with all these things.
I am the one who buys the glut and parses it out to students. But the former professor had the students sizing at their homes with their own purchased formaldehyde...
However, don't med students get exposed to formaldehyde all day long with cadavers?