Why do spells use yellow paper and cinnabar?

Amulets were originally a product of Taoism, not from Buddhism. Its significance is a symbol of the connection between man and nature. The paper used for amulets has many colors and different meanings, but most of them are painted with yellow paper cinnabar, because yellow is the atrium of five elements, corresponding to the dry soil and Kun soil of Wuji Zhonggong, representing the town taking ten squares and the five elements attached to it. Yellow is also the supreme use of imperial power, representing authority and righteousness. Secondly, cinnabar is blood-red, which represents the fire of Ding, and has the meaning of eliminating darkness and brightness. Moreover, cinnabar has the effect of expelling pestilence. So Taoist amulets are mainly used for this. . . . Yamada Keiko