(1) According to the depth of ink, it can be divided into five levels: dry ink, light ink, thick ink, extremely light ink, and burnt ink, namely burnt ink (original ink), thick ink, heavy ink, light ink, and clear ink;
(2) According to the material of ink, it can be divided into three types: "oil smoke", "pine smoke", and lacquer smoke. Oil fume ink is made by processing with tung oil or added burning smoke; Songyan ink is made by burning pine branches and smoke, while lacquer smoke is made by using Chinese lacquer as fuel and adding glue to the burnt smoke.