RE: A few gum things
Don, > Let me say first that I have zero technical knowledge or training on this topic, but I wonder whether there is any real basis for preferring glutaraldehyde over formaldehyde. > In a word yes! I am one of the gummist <sp?> that Christina was referring to in her post. To make my reply brief; in my testing and practice of gum printing glut works extremely well compared to Formalin, Glyoxal, or chrome alum. Three of the most frequently mentioned hardeners found in modern alt. texts. Glut produces a smooth soft surface that easily allows multiple coats of gum without staining. IMO, (though I can't prove this nor will I try) Glyoxal tends to cause staining and creates a rough stiff surface to coat on. There is no doubt that aldehydes such as Formalin and glut pose serious potential risks to their users. If one isn't comfortable using them then I would suggest that they not use them. Oh yeah did we mention dichromates used with gum printing? Certainly another potentially dangerous chemical component we use for our alt print works. But both classes of chemicals can be safely used, if used intelligently. Sloppy practice means risky practice. I know that two well know and competent printers here on the list had adverse reactions to glut. So there is no doubt that some users have had negative experiences sizing with glut as the hardener. I'm not suggesting that they used the product in a reckless manner, rather that they were very sensitive to the vapors just as I am to Formalin. Formalin, BTW is used in C-41 stabilizer (or it used to be) and it was horrible to work around. My handout given to my workshop students outlines all of the risks associated with the use of these chemicals. In large bold font. I make a point of lecturing sternly about the potential hazards. I have yet to have any student leave and ask for her money back. So yes there is a risk, but it's a hell of a lot less dangerous than driving in traffic everyday - IMO. My practice with glut is to use as little of it as possible and contain vapors as much as possible and to have lots of fresh air while sizing paper. Of course a fairly risk free alternative would be to just make inkjet prints. But wait, weren't you one of the people extolling the virtues of hand made prints vs. inkjet prints recently? Don Bryant
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