Cyan, like Yellow, can be seen directly by looking at the dispersal of White light. However, It is usually seen as a combination of Blue and Green light reflected from objects that absorb Red light when bathed in White light. Again we have no Cyan sensitive cones in our eyes, so the color is always percieved as an equal stimulus of our Blue and Green sensitive cones.

Magenta is percieved as equal stimuli of our Red and Blue sensitive cones. Magenta colored objects bathed in White light absorb Green light, reflecting only Red and Blue light. This is the only way Magenta can be seen, as Magenta does not occur in the visible spectrum. It cannot be seen in the normal dispersal of White light, as can Red, Green, Blue, Yellow, and Cyan.