White contains all colors of light in the spectrum. It is generally considered colorless, with the highest brightness and zero hue. White light is a mixture of three primary colors of light in the spectrum, including red, blue and green, in a certain proportion, and the mixture of all visible light in the spectrum is also white light. Black is defined as no visible light entering the visible range. Contrary to white, it means that all light in the visible spectrum enters the visible range at the same time. If the pigment absorbs all visible light in the spectrum and does not reflect any color light, the human eye feels black; Yellow gives people the feeling of lightness, hope and vitality. Yellow is a color formed by light with a wavelength between 570 and 585 nanometers. Red light and green light can be mixed to produce yellow, and the complementary color of yellow is blue. Traditionally, painters use purple as a complementary color to yellow.