I get that Newton decided to mark seven (or 5+2?) colours, but what was his exact procedure? It seems a stretch to squeeze a full octave in there, for starters. And did he just name those seven colours and ask his friend to mark those off on a spectrum, or did he construct a tempered scale first, according to mathematical principles, and superimpose that onto the spectrum?
Looking at Newton’s colour circle pictured here, it appears that the interval between Blue and Indigo is (approximately) equal to that between Indigo and Violet, but your equally-tempered ratios 488/450 and 450/387 do not match? Also, if we go for your chromatic version, wouldn’t we need to split each of Red, Yellow, Green, Blue, and Violet into two, eliminating each of those colours in favor of two new ones?
Berlin & Kay’s book on it was published back in 1969. The former Perfect Master known as Cecil did a column summarizing B&K’s book. There’s been a lot of research on this topic since, but I’m not aware of any good summary of it.
The source I found yesterday, which cites the B&K book **dtilque **mentions, was “The Linguistic Significance of the Meanings of Basic Color Terms” (The Linguistic Significance of the Meanings of Basic Color Terms on JSTOR) which
(a) may need you to register (for free) to read the 37-page article;
(b) needs $12 before presenting a version which allows copy-paste;
(c) was intended as a partial refutation of B&K’s result;
(d) is more about vision physiology than language variations.
It does mention the Dugum Dani language of which Wikipedia writes:
In refutation of B&K, the jstor article mentions that 69% of Dani informants focused white-warm mola at Red.
And this is ultimately the answer to a question I asked in GQ long ago, of why we see red in violet. It’s not in the cones (sensors), as I had originally supposed, but in the process of sending the visual signal to the brain. It’s a quirk that allows us to identify colors beyond blue by mapping them partly into the red spectrum.
I presume the eye doesn’t just send the raw signals to conserve bandwidth, as it would have to send signals from all the cones and the rods. Instead, some minimal processing occurs.
I did actually use an online source, for convenience. I agree with you that it isn’t super accurate, but I think it can be useful, if what I say turns out to be true on most screens.
First set of numbers: Blue Indigo Violet
Second set of nums: Blue Indigo Violet
I then used GIMP to try and equalize the brightness, for a clearer comparison:
First set: Blue Indigo Violet
Second set: Blue Indigo Violet
Based on these results, the classical gives me what I would call blue, blue-violet, and red-violet. But the tempered gives me the cyan, blue, purple (slightly redder than violet).
I would expect that, to make it harmonious and fit the pure math, he’d use classical. Still, there are those color wheels that look more like he used even temperament. I could see him doing so to try and shoehorn in his theory.
I will finally leave you with this, since you seem to have some expertise, and can critique it: Indigo - Wikipedia
I told you the procedure in my earlier post. Why do you think it’s a “stretch” to “squeeze” an octave in there? You can divide any length by seven or eight.
Incidentally, I suspect that people continue to use “Indigo” and “Seven Colors” because of its long history (and social inertia), because there’s more of a mystic association to “seven” than to “six”, and so that Roy G. Biv will have a pronounceable last name. But they still use only six colors in a rainbow flag ( Rainbow flag - Wikipedia ) and in the Resistor Code ( https://www.instructables.com/id/Resistor-Color-Code-Guide/ )
If you look at the wikipedia article posted on indigo above, there is chart from Newton that does show that each color band was not exactly the same size.
For me, when I look at a spectrum, there just seems to be a blindingly obvious stripe of light blue that seems like it should get a name.
Not sure that’s a significant refutation of B&K, but that’s beyond the scope of this thread. B&K was unpopular among certain sectors of the linguistic world because it violated Sapir-Whorf. Of course, not everyone liked S-W, so it was popular in other sectors.
I know – which is why I qualified my original citation of it. But the rainbow flag I link to is the current officially used one and the most common. The original Rainbow Flag uses two colors that break up its resemblance to a proper spectrum; the current one has six colors and looks more like what people expect to see in a rainbow.
My initial reaction is that the “blindingly obvious” light blue stripe is really an artifact of the way your monitor renders colors (and, of course, would render pictures of rainbows the same way). But, upon studying some actual spectra here at my desk (I’ve got a set of diffraction grating glasses that make me look like a dork when I put them on, but give me instant rainbows), I’m not so sure. That region of blue between green and violet can contain what looks like a lighter stripe of blue.
It was correctly stated above that the colors are not of equal width, whether this is the way they’re seen if plotted on a scale linear in wavelength, or the way the spectrum actually appears when generated by a prism or a raindrop. Yellow is definitely much narrower in extent than, say, red or blue, which take up huge areas. We clearly did not decide upon colors by trying to segregate the spectrum into regions of equal size. But Yellow is, despite its narrowness, so qualitatively different from what surrounds it, and so strikingly obvious that any scheme that rejected “Yellow” as a color would never be accepted and used.
By the way, as I observed above, not all rainbows look the same – the presence or absence of colors, and their relative widths, depends upon the sizes of the raindrops 9and, knowing the appearance, you can tell what size the drops are). And the appearances of the rainbow spectra are different from the appearance of a spectrum made by a prism, and what comes out of a glass prism is different from that produced by a salt prism, which is different from what is created by a diffraction grating,… etc and etc. and so on. The relative widths of different spectral regions really does critically depend upon the dispersion of the medium or the number of diffraction lines and the geometry of the situation.
You certainly can, but that does not mean you can play an entire octave between adjacent C and D on a guitar string. Taking [from Wikipedia] the extreme bounds 380-740 nm on the visible spectrum, they nearly make an octave, just a quarter-tone or so short.
From Newton’s description of his procedure and your own description of it, I gather that he projected a spectrum onto the wall through a prism, then asked his friend to delineate both the seven bands and the center of each band, having named the seven colors beforehand. (Also, he only tested one friend?)
You certainly can, but that does not mean you can play an entire octave between adjacent C and D on a guitar string. Taking [from Wikipedia] the extreme bounds 380-740 nm on the visible spectrum, they nearly make an octave, just a quarter-tone or so short.
From Newton’s description of his procedure and your own description of it, I gather that he projected a spectrum onto the wall through a prism, then asked his friend to delineate both the seven bands and the center of each band, having named the seven colors beforehand, including Orange and Indigo. (Also, he only tested one friend?) He concluded that the boundaries between bands “about” divided the interval into certain proportions: 2/9, 1/3, 1/2, 2/3, 4/5, and 7/8 of the length, starting from the violet end, confirming to himself the musical analogy. Do I have all that right?
Rainbows aren’t seven colors or three colors; they’re an infinite number of colors. And those infinite number of colors aren’t from blends of some finite number; the finite number is from the limitations of how human eyes work.
Quick reply because your comment caught my eye: This cannot be correct. I have seen a simple demonstration at the Benjamin Franklin Institute in Philadelphia (once upon a time when this museum really cared about science). When one blends the three primary colors of light, one creates white light.
