My turn on the soapbox:
In my painting classes at school a bunch of us got more than a little
carried away with that process! :) It can be done to almost anything
with a paper backing. RC paper will NOT work! At least, it dosen't look
too good. Fiber paper is ok, but remember that all the light values are
created by the paper that you are removing. Book type can be grabbed by
the emulsion pretty easily. (Money transfers pretty well but that's
illegal) Polaroids....hmmmmm I bet they would work almost perfectly,
considering it would be almost a perfect emulsion to emulsion bonding!
But I haven't seem it tried YET. I might have some results by
tommarrow....
Regg.