Strathmore 3 1/2" X 2 1/2" Watercolor Paper is great as an ATC base. 10 - 140 lb. heavy weight paper. It has a professional grade, cold press surface which is ideal for mastering watercolor techniques. Strathmore Watercolor paper is the ideal, traditional surface for creating beautiful watercolor ATC paintings. This heavy weight, bright white paper absorbs color in all its richness and is suited for watercolor techniques, as well as pencil, pastel, gouache, pen and ink. Paper measure 3 1/2" X 2 1/2" and comes in a pack of 10. Acid free.