Dye and pigment cannot be distinguished by discoloration of water. The difference lies in the different coloring methods of objects. Dyes can penetrate into the interior of objects for coloring, such as the interior of fibers. Paint can only be applied to surfaces, such as cloth.
The details are as follows:
Pigment is a fine powdery colored substance, generally insoluble in water, oil and solvents, but can be evenly dispersed in it. Pigment is the secondary film material of color paint, in the process of wood decoration modulation primer, putty and wood color, also often use pigment. An opaque paint coating that has some color and masking power due to the addition of pigments. At the same time, pigment can enhance the durability, weather resistance, wear resistance and so on.
Unlike pigments, dyes are colored substances that are soluble in liquids such as water, alcohols, oils, or other solvents. Dye solutions can seep into the wood and undergo complex physicochemical reactions with the wood's components (cellulose, lignin, and hemicellulose), which can stain the wood without obscuring its texture and give it a bright, firm color.