What maybe surprising, is that while there are equal numbers of cones sensitive to generally red, and generally green, there are only 10% of cones sensitive to generally blue. It has been argued that the human eye has evolved to compensate for the excessive amount of blue light in the environment scattered from the gasses of the atmosphere in daylight; however, that does not explain our response to pink-amber light, that is produced when the atmosphere becomes too dense.

The brain is able to fill in (reconstruct) gaps of detail missing in an image. It is also capable of creating successive images, a curious effect discovered by a French chemist, Michael-Eugene Chevreul circa 1840, when he also discovered the phenomenon he called " simultaneous " or " reciprocal contrast ", based on the principle of complementary colours.   Click on the primary coloured kites.   Look at the Magenta, cyan, and yellow kites for 30 seconds, then look up at the white space above, and you will notice an almost fluorescent appearance of an after image of the kites in their complementary colours; green, blue, and red.   Primary Kites