Dear Ralph, I find that matte, overmatte, and frame serve as a good barrier to prevent unwashed chemicals leaching out of the prints that I do and eating into the plaster walls. I used to put glass over them but I find that the excess mercury leaching out of the larger pictures tends to condense on the inside and drip down out of the bottom. It is easier just to hose them down at the start of the exhibition and then once a day after the school children have left the gallery. You have to be careful not to do it on the grass or the city council gets nasty. Uncle Dick ============================================================================================================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.