I will tell you the «terrible secret». The colors don’t exist.
I mean that the visible objects have no color; they only reflect the incident light of a certain length. Ordinary «white» color consists of various colors, which is illustrated by the rainbow. Do you remember: “ROY G BIV”? 🙂
Take a set of colored glasses and markers of the same colors.
Write «Borjomi» on a sheet of paper with a red pencil and then look at the sheet through the red glass. The inscription has disappeared! Because red glass lets pass only the red color.
Write on a sheet of paper with green felt-tip pen «To your health» and look at the sheet through the green glass. The top line is visible, and «To your health» is not. Because green glass lets pass only green.
The “invisibility» of red color of the cover of Borjomi when you look at it through the red glass is particularly impressive! The trade red color is not visible on the cover.
Colored glass lets pass almost all colors except some narrow range. For example, the wavelength of «red» color is from 620 to 740 nanometers.
And now do you understand the expression, attributed to Confucius, the «black cat in a dark room”?