calendar -Lignin free and acid free matboard -Thickness:2.0mm -Core: ... , carboard, pre-cut matboard and matboard calendar) . Our products can be used for matting photos, art and also great for crafts, signs ... of surfaces and sizes8. can be used for matting photos, art, and needlepoint. Also great for crafts, backboards, signs, children's ... with calcium carbonate to alkaline reserve of 3-5% desk calendar