The Big Think

November 7, 2014

Magenta Ain’t A Colour – StumbleUpon

Filed under: Science — jasony @ 10:43 pm

Magenta Ain’t A Colour – StumbleUpon: “

If the eye receives light of more than one wavelength, the colour generated in the brain is formed from the sum of the input responses on the retina. For example, if red light and green light enter the eye at the same time, the resulting colour produced in the brain is yellow, the colour halfway between red and green in the spectrum.

So what does the brain do when our eyes detect wavelengths from both ends of the light spectrum at once (i.e. red and violet light)? Generally speaking, it has two options for interpreting the input data:

a) Sum the input responses to produce a colour halfway between red and violet in the spectrum (which would in this case produce green – not a very representative colour of a red and violet mix)
b) Invent a new colour halfway between red and violet

Magenta is the evidence that the brain takes option b – it has apparently constructed a colour to bridge the gap between red and violet, because such a colour does not exist in the light spectrum. Magenta has no wavelength attributed to it, unlike all the other spectrum colours.


  1. Best thing I’ve learned all day. Of course, it’s only 9:34am.

    Also see The Oatmeal’s article on mantis shrimp for more color perception mind-blowingness:

    Comment by seanmctex — November 9, 2014 @ 9:35 am

  2. I lost a game of ’90’s Trivial Pursuit’ because they asked a question about colors of the rainbow.
    It was a ‘gotcha’ question because in the 90’s they dropped Indigo from the ROY G BIV mnemonic.
    Like Pluto, Indigo was tossed aside because of ‘science’.
    Apparently there wasn’t really enough room between Blue and Violet to hang onto Indigo as a named component in the rainbow.

    Comment by Josh — November 10, 2014 @ 9:41 am

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