Watercolor paper is artists' paper which has been designed specifically for the watercolor medium. It is usually specially treated to make it less absorbent, so that the watercolors will not bleed and muddle together on the paper. Watercolor paper comes in a number of different grades and styles, and most artists experiment with several different types before they find a style which works for them.

Many art supply stores carry watercolor paper, as do online retailers. When first working with watercolor paper, it is a good idea to go into a store to pick some out, so that you can feel different textures. Once you find a type that works for you, you may be able to find it more cheaply using your favorite search engine.

There are three primary components which impact the look and feel of watercolor paper. The first is how the paper is treated, the second is how the paper is processed after manufacture, and the third is weight. All three of these factors should be taken into consideration when selecting watercolor paper. In addition, artists should be aware that watercolor paper comes in both loose and bound forms, and in different sizes. The paper is also available in the form of a watercolor block, which is glued down on all four sides, making it like a portable clipboard full of paper.

Most watercolor paper is treated with gelatin, which coats the fibers of the paper so that they cannot absorb water as readily. When the gelatin is mixed in with the fibers before the paper is made, the watercolor paper tends to be of a higher quality. Other manufacturers paint a coating on later, which can become an issue if an artist scratches or gouges the paper.

A lot of companies still hand form watercolor paper on paper screens. When the paper is pulled out of the screen, deckled edges are created along the edges of the paper. These edges are soft and wavy, and are favored by some artists for although they do not have an impact on the quality of the paper. With a light hand, deckled edges can be dyed to contrast with the piece or be more ornamental.

After watercolor paper is removed from screens, it may be cut and packaged for sale as is, creating “rough” watercolor paper. This watercolor paper has pits and grooves in which paint and pigment can pool, creating a rougher finished piece. The watercolor paper may be further processed by being run through rollers to relax and smooth the fibers. Cold pressed watercolor paper is run through cold rollers, while hot pressed watercolor paper, the most smooth kind available, is run through hot rollers.

Well labeled watercolor paper will indicate which processing technique, if any, was used. In addition, the label will have information about the weight of the paper. Weight is determined by the combined weight of 500 sheets of paper of a standardized paper. Heavier paper is less likely to curl and warp, although watercolor papers with a high rag content will need to be stretched before use, or they will buckle. To stretch watercolor paper, the paper is moistened and fastened to a dry board, pre-treating it so that it will not shrink when it is painted.