</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Jorge @ Sep 24 2002, 12:15 PM)</td></tr><tr><td id='QUOTE'>Hi all, since I moved to Mexico, shipping costs for materials are eating my lunch money. I usually have done the sizing with 250 bloom gelatine. Today I saw a box of unflavored Knox gelatine and decided to buy it and test to see if it will work for pt/pd but I would really appreciate to know the experiences of someone who has used it. What bloom is it? processing tips? did it change the color of your prints? etc, etc. Later...........</td></tr></table><span id='postcolor'>
I've experimented with a few sizing agents, mainly for gum printing. I've always found the Knox the least suitable. I believe it is around 80 bloom (although I can't remember where I read that several years ago). I think the best thing is to just bite the bullet and go with the 250 from B&S as it is consistent. Another alternative which I use for gum printing is canvas hide glue sizing and it is my favorite when I want to try avoiding subsequent hardening. It is available in most art supply stores, is less expensive and apparently harder than the gelatins, but slightly yellower.
As far as the hardener, I'm not sure that glyoxal is really less toxic than formalin. It doesn't irritate as quickly as formaldehyde, but if you can smell it, you are probably lacking adequate ventilation for using either. (Just like some newer artists' paint solvents don't smell as bad as traditional turpentines so some people expose themselves to the fumes longer...there's some reciprocity going on there.) Glyoxal certainly doesn't harden as well in my experience.