Paper made with natural cotton fibers on a cylinder-mold machine Great for watercolor, gouache, acrylic, and airbrushing Made with a natural gelatin sizing Natural white, acid free, 100% cotton paper. Arches Watercolor Pads contain paper made with natural cotton fibers on a cylinder-mold machine. This artist-grade watercolor paper is great for watercolor, gouache, acrylic, and airbrushing. Arches is made with a natural gelatin sizing. These pads contain 12 sheets each of natural white, acid free, and 100% cotton paper in a fold over pad. This pad is 9"X12" hot press 140lb / 300g.