Watercolor Paper by Arches. Details:Arches watercolor paper is made the traditional way, using a cylinder mould. This method ensures that the fibres are evenly distributed which makes the paper extremely stable, so it will not warp or stretch when water is applied to it. Arches watercolor paper is made from long, 100Percent cotton fibres, allowing it to absorb a lot of water without warping or causing the colors to bleed. It is sized to the core with natural gelatin, so it can be scratched without tearing or linting. This Internal sizing also prevents paint penetrating into the paper, allowing light to shine through the pigment and reflect off the paper while ensuring durability of the colors.