The basic rules are: keep your print away from light and humidity and, if the work is matted, be sure to use an acid-free mat board (or “museum board”). Useful texts on proper care of works of art on paper are:
Anne F. Clapp
Curatorial Care of Works on Paper: Basic Procedures for Paper Preservation.
(Oberlin, Ohio: Intermuseum Laboratory, Allen Art Building, 1978; revised and augmented edition New York: Nick Lyons Books, 1987)
Francis W. Dolloff and Roy L. Perkinson
How to Care for Works of Art on Paper.
(Boston: Museum of Fine Arts Boston, 1979)
Margaret Holben Ellis
The Care of Prints and Drawings.
(Nashville, Tenn.: AASLH Press, with the assistance of the J. Paul Getty Trust, 1987)