There are two kinds of dyes mastered in Han Dynasty: plant dyes and mineral dyes. The main plant dyes are: (1) bluegrass. Indigo extracted from it can dye cyan, and bluegrass was widely planted in the Northern Han Dynasty. ② madder. The squeezed juice can be dyed red, called "crimson" color. (3) safflower. It is a plant introduced from the western regions in the Han Dynasty. The red color of safflower is called "Zhen Hong" (big red). (4) Gardenia. Fruit contains yellow pigment, which is a direct dye and can be dyed orange. "Han Gong Yi" records: "Dyeing gardens produces flowers, and flowers are dyed into royal clothes." It can be seen that gardenia and daisy are high-grade dyes. ⑤ Oaks, acorns and gallnuts. These plants contain tannic acid and ferric salt to generate ferric acid precipitation per unit area, which can be used to dye black and have very stable performance. Plant dyes include Sophora japonica, Hollyleaf, lotus seed shells and Chinese tallow leaves. Mineral pigments mainly include cinnabar, lead white, sericite and carbon black.