Jim, if memory serves me correctly several of the prints from 'In the American West' were mounted on aluminum. And since there will be a retrospective in Sept at the Carter here in FW, why not catch a flight back down then and we can go see them
I really do not know how they were attached other than I recall the corners were not taped and it really looked like the emulsion was ON the aluminum. Will have to check Ms. Wilson book and see if she metions it...will post an update if I find out.
BTW, it was great meeting you at the workshop