Regarding the hardening in glyoxal: Thanks to Judy's info I switched from
formaldehyde to glyoxal and find it excelent. The only thing I am not yet sure
of is: how effective is it compared to the formalin? So maybe I didn't yet find
the lowest possible concentration. But to harden the final print this may not be
that important, as the relief consists of hardened gelatin allready. I only must
use it prior to the final wash because right now I do the double transfer method
with a final transfer from the plexi (which serves as an excellent temporary
support for development) to a final support paper coated with unhardened
gelatin.
Klaus Pollmeier