Purple is composed of warm red and cold blue, which belongs to secondary color. In China tradition, purple is a noble color. For example, the Forbidden City in Beijing is also called the Forbidden City, and there is also the so-called "purple gas coming from the east".

2. yellow

Yellow (English: Yellow) gives people a relaxed and happy feeling, full of hope and vitality. The optical complementary color of yellow is blue. But traditionally, painters use purple as the complementary color of yellow.

3. Green (surname); green

Green is a common color in nature, darker or brighter than grass, and it is also a color between yellow and green in the spectrum.

4. White (last name)

White is a color that contains all colors of light in the spectrum and is usually considered as "colorless". White has the highest brightness and colorless phase.

White light can be obtained by mixing the three primary colors in the spectrum: red light, emerald light and indigo light in a certain proportion. The mixture of all visible light in the spectrum is also white light. This color represents the purity of the moment.

5. Black

Black is basically defined as no visible light enters the visible range. Contrary to white, white means that all the light in the visible spectrum enters the visual 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 will feel black. If the pigments of the three primary colors are mixed in a proper proportion, and the reflected colored light is minimized, the human eye will also feel black.

So black can be caused by insufficient light (night) or by absorbing all colors of light (black pupil).