Thanks so much, Britt, for taking the time to pass that information on to the list!! I find that clients occasionally expect me to know about paper conservation and lightfastness of pigments, etc ( for those who buy 'hard copy' water colours, etc.). Also, I am interested for myself... I have done quite a few carbon dust fish illustrations where I mounted the fragile clay-coated board to a rigid backing using rubber cement as an adhesive - a total no-no these days! The clay will probably slow down the damage from the rubber cement but one day it will no doubt show through. I know there are hundreds of my and other's illustrations out there in storage at the local museum and university. What a shame, but we didn't know... Karen Karen Uldall-Ekman [log in to unmask]