Human eyes can distinguish 10 million colors, but have you ever thought about what color the mirror is?
You might say silver because they are made of metals such as mercury or aluminum. But in fact, it is not the color of an object, that is, the color that it cannot absorb light waves. For example, lemon absorbs all other wavelengths of visible light and reflects yellow light into your eyes, so you can see yellow. The reason why a piece of white paper looks white, most people will say, of course, is that it reflects light of all wavelengths, so it shows white, but is it really so?
If there is a completely transparent glass, the reason why you see the object in front from behind the glass is not that it passes through all light, but because the intensity distribution of light does not change when it passes through the glass. The projection of light with different intensities allows you to see the appearance of the basic object. Then, when we adjust the transparency of the glass, although the transmitted light decreases, the distribution of light intensity does not change, so you can still see the object. If there is completely transparent frosted glass here, what color will it show? The glass is completely transparent, but what you see is a piece of white, because the frosted plate completely disrupts the intensity distribution of light. Macroscopically, it is uniformly white, so the white object looks white, not because it reflects all light, but because the intensity of light reflected on the surface of the object is completely disrupted, and the light intensity looks uniform, Appears white.