A powdered substance used for coloring. It is insoluble in water, grease, resin, organic solvent and other media, but can be evenly dispersed in these media and can make the media colored, and has a certain covering power. The basic requirements of pigments used in art are that the finer the particles are, the brighter the color is, and the longer the color is, the better the stability is. Watercolor pigments are almost transparent except white. This can meet the needs of watercolor cover dyeing.

The gouache pigment was originally invented by adding white powder to the watercolor pigment to make the color opaque. Because watercolor paint is transparent, it is difficult to modify it once the painting is wrong. The gouache pigment can be easily modified because of its opacity. Later, raw materials such as gum arabic were added to gouache pigment to further improve its performance. Arabic gum can make the surface of gouache paint have a layer of gloss after drying, but in special occasions where flat coating is required (such as painting effect pictures and coloring for animation), the gum will form irregular spots on the color surface, or make the color uneven, so there is a special degumming pigment.