So did I. I have had the final transfer paper in the cold water for
hours, esp. during workshops, and didn't notice a problem. This was
Hanfstaengl transfer paper, which is hardened during manufacture by
adding chrome alum to the gelatin. But also my self coated Fabriano
(hardened with formalin then...) caused no problems. I just throw as
many sheets into the water as I think I'll need during that darkroom
session.
With the exposed pigment tissue it's certainly different. Although
sometimes the transfer even works with 20C water and high humidity, I
found it MUCH safer to keep to 15-17C and 50% rH. In winter I don't have
problems with this, but in summer time I need a dehumidifier (which
dries the air but at the same time warms it up...) and cold water from
the refridgerator.
Klaus Pollmeier