Comment by simpleTruth

What your missing is the concept that RGB colors are based not around the physical property's of light but the eyes ability to detect light using Rods and cones. In the real world there is a difference between 390 nm light and 390.00001nm light all the way up to749.9999 nm. However all of that is abstracted away and the eye only really cares about the relative intensity of RGB when there is enough light or just B and W in really low light conditions.

So, to fool a machine you might need to exactly match all the individual wavelengths relative intensity but with a human you get to ignore most of that and just look at 3 numbers per pixel.

PS: A small number of people can detect 4 colors but the net effect of this is almost meaningless for various reasons.