What are the concepts of three primary colors and three light colors in photography?

The three primary colors of light refer to red, green and blue. Different from the three primary colors of color (red, yellow and blue), the initial condition of the three primary colors of light is that red, green and blue light are constantly superimposed in an all-black environment, and finally white light is obtained. ; The initial condition of the three primary colors is a white object, and the three colors of red, yellow and blue are constantly superimposed to form a black object.

In addition, red light and green light form yellow light, red light and blue light form red light, and blue light and green light form cyan light.