Color appearance and the end of Hering’s Opponent-Colors theory

It will always be worse the more complicated something is. One particle is hard. A hydrogen atom is harder. Oxygen is just this side of impossible. Molecules are impossible and you just start throwing away vast numbers of terms. By the time you get to an eyeball, much less a brain, you are basically just guessing and hoping you can cover some of the cases some of the time.

Once could argue that our eyes can't even "hear" a fifth. The amount of data our ears extract out of basically two points is amazing. Our eyes in the meantime take an entire spectrum and come up with "blue-ish".

What’s left of the scientific method if people don’t? I think reproducibility and inertia („science progresses one death at a time“) are problems, but I hadn’t thought that induction could be one.

That would be fine, so long as you don't use an RGB display to display those colors.

The RGB color space is severely limited when compared to the colors a person can see. This becomes obvious as one plots color spaces on a CIE 1931 diagram.

Here's a simple tool to see some of this (recommendation: move "system gamut contrast" slider to 50%). Select a working color space from the pulldown to see how much of the visible range it encloses (or discards).

https://demonstrations.wolfram.com/CIEChromaticityDiagram/

A typical REC709 color space throws away over half the colors a person can see. In other words, as I said, using a monitor to run color experiments can be a serious mistake. Color Science can be strangely complex.

There is a company trying to push the envelope in display technology and encourage industry to move primaries beyond RGB. The results, based on prototypes, can be impressive:

https://6pcolor.com/

Disclosure: We have done color science, software and hardware consulting for 6P.

But also I wonder how those kinds of decisions end up coloring so to speak AI. Training a model on image compression designed to fool the human eye is basically forcing it to reverse engineer the human eye.

I teach painting in an art school. The huge problem with almost all pallet choosing apps (e.g. Adobe's https://color.adobe.com/) is that they produce swatches: a small collection of discreet color values (e.g. red, green and yellow). These would present as peaks in a hue histogram. These swatches would be great for choosing a color scheme for your kitchen, but are not suitable for a painter.

I have looked at more painting hue histograms than any man alive, and I can tell you that almost all painters employ ranges of colors. The hue histograms present as 'pie slices' on the histogram, not peaks. Hence: a wide pie slice of greens (plural) and s narrow pie slice of reds. Show me a color picker like that and I would likely share it with my students. As it stands, I warn against them.

Even ignoring color blindness, there's the fact that some people see significantly more range of colours than others (I am one).

Women tend to be more sensitive to slight variations than men (surmised to be evolution ensuring they can better gather from plants , knowing ripeness etc). I see even more variety than that norm.

Human vision is funny, because the majority actually don't see much, with some seeing even less, and some seeing so much they can perceive parts of the UV and Infrared spectrums (not pleasant since our world is absolutely not designed for such people).

It seems unlikely that AI could actually do well accommodating all the variations and would almost certainly be focused on averages while ignoring the color blind and "advantaged".

> The essay reviews the psychological and physiological evidence for Opponent-Colors Theory and concludes the theory is wrong.

Am I supposed to interpret “Opponent-Colors Theory” as something specific and different from the general concept of opponent colors?

I think that what they are saying is that linearity is part of the status quo of Opponent-Colors Theory and they reject the whole thing including the linearity. So in essence they agree with you.

Because that’s how color was encoded: as high frequencies in the spatial scan. This was conveniently backwards compatible with analog black & white TV, at the expense of color accuracy (which is why the standard was sometimes called “Never Twice Same Color”.)

https://en.wikipedia.org/wiki/Color:

“Color (American English) or colour (Commonwealth English) is the visual perception based on the electromagnetic spectrum.”

⇒ colors aren’t coded; they are created in the brain. Outside it, all there is are light spectra.

> Or rather, the brain assumes that spatial frequencies coincident with the cell spacing are most probably because the object is that color, not because the object is weirdly striped as black and white in exactly the same pattern as the retina.

So, how do you explain that subjects do not change in colour when you move closer to them or further away, or when you divert your gaze (cone cell spacing is far from uniform across the retina)?

In all languages, the circle of hues is partitioned in a number of regions, which have distinct names. The number of these regions varies from language to language, usually between two and eight. The value of this number has much less to do with the distinctiveness of the colors, than with the necessity of describing the colors of the objects that had a high probability of being subjects of conversation for the speakers of that language. Many languages have a single word for the colors green, blue-green and blue, just because there were no common objects for which it was necessary to specify whether they were green or blue.

The too much repeated myth that the Ancient Greeks did not have a word for blue was created by people who might have known some linguistics, but who were ignorant about chemistry and mineralogy.

There are plenty of dictionaries and commentaries about Ancient Greek literature which are very wrong about many words, because their authors did not understand what they have read, for lack of knowledge about the natural sciences. For instance, when Homer speaks about "miltos" used to paint some ships, you must understand that this word designates what is now called hematite or ferric oxide, which was processed as a red pigment. Or else when Plato speaks about the grains of diamond found together with alluvial gold, that has nothing to do with what is now named diamond (which became known to the Greeks only later, after the expeditions of Alexander the Great), but "diamond" was the name for nuggets of native osmium-iridium-ruthenium alloy. Understanding this meaning makes clear why Hesiod said several times that diamond is gray and why he considered it as a material from which a blade could be forged by someone with superhuman strength.

There are many references to blue in Ancient Greek literature and the normal word that was used has been borrowed in English as "cyan". "Cyan" has never meant blue-green in Greek, but only plain blue. "Cyan" initially meant the color of the painting pigment that is now called "ultramarine blue", but later it was also used for the cheaper blue pigments Egyptian blue and azurite. An alternative way to refer to blue in Greek was as the "color of the air", which meant the color of the sky.

In Latin, blue was normally called as the color of the sky, while the word used for green, "viridis" meant either green or blue-green. When these two colors had to be distinguished, the former was described as green like leaves or like grass or like emeralds, while the latter was described as green like the littoral sea or like turquoise or like beryls.

Similarly, the word used for red in Latin (and also in Greek) meant either red or purple, and when the two colors had to be distinguished, the former was described as red like the dye extracted from beetles (crimson), while the latter was described as red like the dye extracted from marine snails.