Museum Series Claybord is made using 1/8" hardboard and features a kaolin clay ground formula that's archival and acid-free. The surface is sanded to an ultra-smooth, highly absorbant finish that allows paint colors to remain true and brilliant. Work into the surface by thinly applying paint or ink, then remove it, reapply it, even scratch through it to add contrast, texture and fine details. Clayboard can be used with inks, egg tempera, acrylics, collage, pencil, pen, airbrush, photo-transfers, casein, watercolor, gouache, mixed-media, and to mount papers, prints and fabrics. The cradled frames are made with premium grade 13-ply birch plywood for maximum stability and a clean, finished look from edge to edge. Made in the USA.