Re: How to super harden papers?

If you tested 10% glyoxal at reasonably alkaline pH (add a bit of
borax to make pH of 8 to 9) and gave a few minutes of treatment at
room temperature, and saw no beneficial effect, I do not think what
you are after can be achieved by any hardener. The fact that you are
using superhart Kodak paper also makes me think that the effect you
are after won't be found by additional hardening of gelatin.

Can you think of other reasons? Matte surface papers contain matting
agents while glossy surface papers don't. If matte surface works for
you, this is one possible factor that comes to my mind.

--
Ryuji Suzuki
"Well, believing is all right, just don't let the wrong people know
what it's all about." (Bob Dylan, Need a Woman, 1982)