Sorry. That's shorthand for Wm Crawford's "Keepers of Light," which is a
pretty good all around source for these processes...
I am now putting one tenth of one percent alkali in the glyoxal, by the
way. That was 4 grams of sodium hydroxide to the gallon of working
solution, for a pH of about 8 and three quarters, measured on chem prof's
pH meter. It turns it a light yellow, which doesn't stain the paper, but,
aside from making the linkage of the glyoxal more permanent, it preserves
it -- the working solution otherwise goes off in a couple of days,
polymerized -- at least mine did. And with students hardening paper all
month, I was running out of glyoxal too quickly. However, Paulchemprof
suggests trying sodium bicarbonate instead, for a reason I didn't
understand, but I will....
Judy