What do we see with our rods and cones? When all the cones are stimulated equally the brain perceives the color as white. The brain is the actual interpreter of color. The average number of colors we can distinguish is around a million.
A million colors; single photons; galactic realms quintillions of miles distant – not bad for the blobs of jelly in our eye sockets, wired to a 3 pound sponge in our skulls.