Colour illusions: What do they tell us about the mechanisms of colour vision?
"We see all colours as made up of four unique (primary) colours- red, green, yellow, and blue. Many vision scientists believe all human colour vision can be explained once brain mechanisms for these unique colours (unique hue channels) are found. However, there is no convincing evidence for such unique hue channels, either from cell recordings or from perception experiments. We have recently got convincing perceptual evidence for these elusive unique hue channels studying some colour illusions."