Sandy
After I sent my note I realised that a photograph on a sculpture is likely to
have to withstand some fairly heavy handlng. I think the practical answer is
going to be photo-etching using dichromated fish glue as the resist, or if you
are using copper, Autotype carbon tissue which is good for making carbon prints
as well.
If the the need for a solution arises in reality I can give you specific answers
to specific questions.
Terry King