GRGR (8) Mauve, Coal Tar & Seances, Part 2

[Joshua T]

susanargus says:

>the whole magenta field of colors (including mauve) relies
>on stimulation of the red and blue sensors in the eye without
>the green sensors in between.  with the rest of colors, the
>eyes process the wavelengths and take a sort of "average wavelength"
>that equals a 400 meter wavelngth or 700 or whatever.  but
>with output both in the red and blue but no green in between,
>it doesnt work to take an average: your blue and red would
>equal green!  so the eye perceives mauve.  a color that doesnt
>exist in reality, that has no equivalent wavelngth.
>
>pretty cool.


That is to say it's not a spectrum color, right?  In other words (which I
picked up at http://www.whatis.com/cmyk.htm ), nothing "radiates" magenta,
but magenta is a pigment, and magenta things reflect just red and blue
light ("mainly").  That is cool.  But I'm not sure that I understand the
"doesn't work to take an average" part.  Does this mean, rather, that we
can infer that our eyes don't work out an average between the red and blue
wavelengths, because if they did, we'd see green, but we don't (we see
magenta)?  (Looks like a good argument to me.  But I don't know this stuff;
I'm really asking.)

Josh