These canvas panels are sold in a huge array of sizes to compliment the various needs of artists at all skill levels. Although the primer is acid-free, the wood core, adhesive and backing are not, so these panels are not recommended for archival work. These panels feature 8oz 100% cotton that is double primed to take all media well. The surface texture is perfect for many techniques, and may be further coated as needed by the artist. Unlike cardboad panels, these 3mm wood core panels have less tendency to warp. In sizes over 16x20", a 4mm wood core is used to insure structural stability.