Single-ply (.0129" ± .0005" ) thickness. Strathmore Museum Mounting Board successfully challenges the effects of time, as well as the environment, upon ­valued works of art. The surface is designed to deliver a smoother, cleaner cut. The colors are solid throughout the board and meet the Library of Congress Standards for Archival Properties. Please note that this single-ply museum board is NOT as thick as most single-ply mounting boards. It might be compared to the weight of poster board or heavy cardstock. As such, it could be used as a drawing surface instead of a matting/presentation board.