Pigment refers to the substance that can make objects colored. There are soluble and insoluble pigments, and there are differences between inorganic and organic pigments. Inorganic pigments are generally mineral substances. Humans have long known to use inorganic pigments to paint and paint their bodies on rock walls using colored soil and minerals. Organic pigments are generally taken from plants and marine animals, such as indigo, gambog and purple extracted from shellfish in ancient Rome.

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.