Harmony Watercolor Paper Blocks feature surface sizing, allowing for easy corrections on wet paper. The natural-white 140 lb. (300gsm) paper is acid-free, light-resistant, features extreme longevity and is eraser-resistant. Masking fluids or masking tape can be used and removed residue-free. Especially suited for wet painting techniques such as watercolor, glazing, mixed media, gouache, tempera and acrylic. 12 sheets per block.