The Lineco Kensington 100% Rag 11x14, 4 ply Matte Boards are manufactured from 100% select cotton fibers. These museum quality rag boards feature a 3% calcium carbonate buffer to guard against acid migration. The slightly alkaline pH level of 8.5 enables it to resist fading, discoloration, and embrittlement. It is the standard for museums and galleries. Ideal for both matting and mounting prints, watercolors, etchings, documents and letters.