Major gap, sort of halfway excusable
Interesting article on color perception by birds.

Birds have four color cone types in their eyes, compared to three in humans. In theory, this enables birds to discriminate a broad range of colors, including many nonspectral colors. Nonspectral colors are perceived when nonadjacent cone types (sensitive to widely separated parts of the light spectrum) are predominantly stimulated. For humans, purple (stimulation of blue- and red-sensitive cones) is a nonspectral color; birds’ fourth color cone type creates many more possibilities.

Nonspectral? Never heard the term before, and it turns out to reveal a MONSTROUS GAP in my basic knowledge. This gap is bothersome because it's right next to my main area of real expertise. Other gaps aren't bothersome. I know that I'm incurably stupid about politics, human strategies, and military matters, so I'm not surprised when a politician fools me for the 1000000th time.

Oddly, this gap is hard to fill from modern sources. I searched long and hard for a simple statement that "non-spectral colors are mixtures of frequencies". Most websites talk all around the basic question, saying that it's not really a matter of mixed frequencies, it's a matter of the perception by RGB cones.

Well, no. Finally found an old pre-1920 book saying clearly that non-spectral colors are chords. The knowledge has been around for hundreds of years, but not part of the usual presentation of the knowledge.

What we "learned" in high-school physics was unclear. We "learned" that every color was present in the spectrum as seen in a prism or rainbow, and we also "learned" that white is a mixture of all the frequencies. The first statement is obviously false, but I never stopped to think about the contradiction.

We DIDN'T learn that all real colors are chords, but that's the plain and simple fact.

Oil painters and house painters understand this simple fact BY EXPERIENCE. They constantly mix the frequencies from different dabs on the palette, or from different cans of flat latex, just as a pianist mixes frequencies by hitting several keys on the keyboard.

There's even a sort of keyboard in most graphics programs, the standard 'color picker'. You mix different numbers of RGB to get the desired color. I use this all the time, but again never stopped to think that these are chords or superpositions of frequencies. I just stuck with the original stupid "learning" that the results are single frequencies as found in the prism. Perfectly contradictory WHEN YOU THINK, but I didn't THINK.

Why does this bother me? Because it's directly parallel to sound, and I've been working with sound and thinking about sound for 50 years. The common descriptions of sound are much more complete. Chords are intrinsic and unavoidable in all discussions of music and speech. White noise is known as a superposition of 'most' frequencies, just as white light is a superposition of all frequencies. All real sounds are mixtures of formants and harmonics, just as all real colors are chords. We can approach a pure sine wave with tuning forks or electronic oscillators, but we can't really get there. No physics book ever conveyed the idea that a major third is one key on the keyboard.

Why is the usual explanation so clear in sound but unclear in light? Quantum crap. The academic understanding of light has been infected by quantum crap since 1926. Quantum has never infected the descriptions of sound.

Later thought: Maybe the convenience and visual simplicity of a prism overwhelmed the complexity of real nature in the usual presentation. There isn't an equally convenient acoustic prism. Acoustic diffraction gratings perform the same function, but they are necessarily large and unfamiliar. You can't keep an acoustic diffraction grating on a lab workbench. Harps and pianos are acoustic prisms, but again they're large and bulky, and they don't separate the notes for visual display. You have to use your fingers to locate the active resonators.

Labels: Answered and unasked, Experiential education

  ¶ 3:10 AM