The primary source of light is the ultimate Sun. It emits white light which is composed of seven colors.
These colors are observed in nature at the time of the formation of the rainbow. And the seven colors of the rainbow are violet, indigo, blue, green, yellow, orange, and red.
Thomas Young found that all the colors could be produced using different combinations of just three colors. These three colors are called primary colors of light.
The primary colors are red, green, and blue.
These primary colors can be mixed in various proportions to create other colors, which are called secondary colors.
Examples of secondary colors include orange, purple, yellow, etc.