[spiraling_shape]

The visual light spectrum starts at around 380nm, if we arbitrarily assign that to be "C", and we ascend(ascending wavelength, descending frequency) from that with the same 12-tone "equal temperament" used in music we get:

C 380

B 402.595975856532 ~violet

- 426.535578357562

A 451.898703701034 ~blue

- 478.769998960052

G 507.239144584613 ~green

- 537.401153701776

F 569.356689213139 ~yellow

E 603.212399747916

- 639.081275592823

D 677.083025786658 ~red

- 717.344477638087

C 760 infrared

With 760 being one "octave" below 380, though the visual spectrum ends at around 740, which means the visual light spectrum is a bit less than one octave.

[jacobolus]

If your ear had only 3 types of detectors which only detected 3 specific frequency distributions within about half an octave but could locate stimuli within your field of hearing with pinpoint accuracy, after a lifetime of using that equipment you would probably be able to make relatively fine distinctions in pitch in that very limited range.

Instead, the human cochlea contains thousands of little pitch detectors spread over 10 octaves, and the perceptual architecture and typical training built around it is designed to detect relative pitches (e.g. noticing the difference between two different people’s voices more strongly than the absolute frequency of the fundamental pitch of either voice).

Eyes and ears just have fundamentally different physical mechanisms and we make sense of visual and auditory stimuli in fundamentally different ways. They are not really directly comparable.

In both cases, however, our perception is strongly context-relative.

[nwatson]

But yellow isn't necessarily just a spike at 569.356... There are plenty of other combinations of frequencies that together will stimulate the green- and red-cones enough to create a perception of (nearly?) the exact same yellow.

[spiraling_shape]

Right. I put the tildes before the color names to indicate that they are "around here".