If you’re concerned about the longevity of your paintings, your best paper choice is acid-free, 100-percent rag paper made from cotton fiber. In general, avoid papers made from wood pulp. They contain at least some natural acids, and will eventually undergo an internal breakdown leading to discoloration and eventual disintegration. Also avoid using framing materials containing acid—for example, mounting boards containing wood pulp or acidic sizing, acidic adhesives or tapes or unsurfaced wooden backing—as the acid will actually move from the secondary source to your paper.
John Kevin Flynn is director of the J.K. Flynn Col., an art restoration and appraisal firm in Brooklyn, New York.