>>13622102First, there are three different colour receptors in your eye, red, green and blue. Which combination is activated determines the colour you perceive.
Second, it depends whether you're looking at a light source or reflected light. Light sources like tv pixels are adding photons to black darkness so the primaries are red, green and blue. Reflected light like from paint is removing photons from white light so the primaries are cyan (red removed), yellow (blue removed) and magenta (green removed).
