I am not sure where I heard this, but a lot of things fly around the
Pt/Pd circles, but I remember several sources commenting on the fact that
the aluminum and/or adhesive on the mounted platinums were in some way
affecting the print. This was also during a discussion about the
addition of irridium to the sensitizer for these prints.
I too am aware and have seen Mr Penn's prints on aluminum. It's just that I
tend to shy away from using any metal in a complex electro-chemical process
like platinum printing. Further complications could arise if gold toning
were an after process. With plenty of other materials around that aren't
metal and work fine, why chance it?
Beside the Taos Humm could be affected by it John!
-- Dick Sullivan
Bostick & Sullivan