Product information "Arches watercolor paper block head glued - natural white 185g" Arches watercolor paper is made in the traditional way on a cylinder mold machine. This paper ensures that the fibers are evenly distributed, which makes the paper very stable so that it does not deform or stretch when water is applied. ARCHES watercolor paper is made from long fibers of 100 percent cotton. This allows it to absorb a lot of water without warping or causing the colors to bleed. It is glued to the core with natural gelatin so that it can be scraped without tearing or fraying. This internal sizing also prevents color from penetrating the paper, allowing light to pass through the pigment and reflect off the white paper, while ensuring the colors are resistant to aging.