Errol: I suggest that you consult CCI Note #10/3 "Storage and Display Guidelines for Paintings". If you do not have a copy of the CCI Notes they are available from the Canadian Conservation Institute, 1030 Innes Road, Ottawa, Ontario, K1A 0C8 (613) 998-3721. Their publications are quite good and are free. Good luck. Susan L. Maltby, Conservator [log in to unmask]