What are the most basic colors?

Answer

Light: the "tristimulus" colors are red, green and blue

the "spectral" colors are red, orange, yellow, green, blue, indigo, violet

Ink: the three-color ink set is cyan, magenta and yellow.

the four-color set also contains black

Paint: in the old days, we always taught red, blue and yellow as the primary colors. Some art teachers are having better results teaching cyan, magenta and yellow as the primaries.