Digital BW, The Print

(Pardon my jumping in.)

Epson Premium Glossy Photo Paper and UltraSmooth share the top spots on the
Wilhelm dark storage ratings (see 9800 test at
http://www.wilhelm-research.com/epson/9800.html) at > 300 years.  Both are
also OBA free.

Glossy paper has a huge dmax, and when sprayed or laminated glossy paper is
probably the most physically durable medium we have.  Between the paper and
coating technologies, I think the surface will be whatever we want.
Bronzing is going to be history soon (and already is if coated or
laminated).

"RC" or "barrier" papers have, in my view, a huge future even at the high
end.   

(But tape-hung matte under glass -- or, better yet, in a www.clearbags.com
envelope -- is still the easiest.)

Paul
www.PaulRoark.com