In the dark night, when we can’t see our fingers, what do we need most at this time ? A lighter ? Or a flashlight ? To be precise, it is light. What we call "light" usually refers to "visible light" that can be distinguished by the naked eye. Visible light mainly comes from natural sunlight and artificial fluorescent lamps. Newton once used a three-dimensional lens to refract the passing sunlight into red and orange colors. There are seven kinds of visible light, yellow, green, blue, indigo, and violet. The object itself will have a "preference" for these seven colors of light. The incident light will be selectively absorbed by the object, and the unabsorbed light will become visible to the naked eye. Color, if an object has no preference for light, it will appear white if it reflects most of the light. If it is penetrated by most of the light, it will be colorless and transparent. However, if it has no preference for light, it will appear white. A lot of light is absorbed, so it appears black. In other words, what we see is actually what the object "dislikes".
The reverse operation of the three-color experiment can combine seven colors of light into white light. However, when the seven colors of pigment are mixed, black pigment will be obtained, which will produce completely opposite results because the two operating mechanisms are different. The pigment itself is not a light source. It only relies on the reflection of visible light to allow people to perceive color with the naked eye. Pigments have different colors because they have their own advantages. The superposition of their own advantages means there is no difference in preference, so it appears black. The same principle is used in the production of dyes, and even the makers themselves may not know it.