Advantages of water-resistant base for photographic papers are reviewed and criteria for selecting polyethylene as the coated layers are listed. Photographic functions of the print side coating, and the need for special addenda are explained. Chemistry of polyethylene is reviewed and chemical mechanisms affecting aging are discussed. Accelerated aging equipment and data handling techniques used in evaluating variations in formulation are described for both dark storage and display conditions. Improvements in formulation of RC base that will prolong product life in display modes are described. Recommended handling and storage conditions designed to extend the life of all photographic prints are reviewed.