Why is the wet rubbing fastness relatively poor?

Reactive dyes, direct dyes and other water-soluble dyes have a certain affinity for water molecules. In addition, according to the molecular diffusion theory, the diffusion speed of molecules in gas, liquid and solid media is higher than that of liquids, and liquids are higher than solids. Since water molecules act as a medium for dye molecules to transfer between the contact surface of the dyed fabric and the white fabric, they are liquid, which is beneficial to increase the diffusion rate of the dye molecules. Therefore, under normal conditions, the wet rubbing fastness of the same dyed substance to be tested is significantly lower than the dry rubbing fastness.