no offense, but sometimes I think alot of folks don't really give a hoot about this stuff, or different ideas about it--other than some generic concept. I can't get beyond an answer that's like shop-talk for me, or spinning off into the day-to-day/real-life type workings of a museum....I posted a month or two ago to that thread about print longevity--and put up links to an interactive on the IPI site, as well to Wilhelm's entire book which is available free as pdf's now. I linked to an admittedly technical, dry paper on inkjet issues as well and a website dealing with air pollution in archives and museums....why bother with this stuff, hell I doubt anyone ever looked at it because it's not a simple answer--maybe it would require some thought.