2.1.3.1　Skin color

Normal skin color is mainly determined by two factors.One is the pigment content in the skin，including melanin，carotene，etc.，and the other is the anatomical difference of the skin，mainly including the thickness of the skin，especially the thickness of the stratum corneum and stratum granulosum.Melanin is the main pigment that determines the color of the skin.(https://www.daowen.com)