Digital BW, The Print

There is a very good article on "Predicting the Life of Printed 
Images" and why it is almost impossible to pin down. The article is 
in the March/April 2003 Photo Techniques. It is by Eric Everett a 
tech specialist at Q-Panel Lab Products, a manufacturer of light 
stability and weathering test equipment.

Vinny
http://www.wulfsden.com