The challenge with color spaces is that the fundamental goal is to reproduce human perceptions not a physical quantity. Color spaces are about human biology, p

The challenge with color spaces is that the fundamental goal is to reproduce human perceptions not a physical quantity. Color spaces are about human biology, physiology and psychology, not about physics. To a first approximation, humans perceive color on the basis of three different kinds of light sensitive "cone" cells. The three varieties are most sensitive to red, green, and blue light. An image with control over intensities of a red, green, and blue component of emitted light can match the stimulation of cones over some range ("gamut") of colors a person could perceive. Orange wavelengths of light are between the wavelengths of a pure red and pure green, and a mixture of red and green light will be perceived as orange. The only reason the RGB approximation to color works is because of how the human eye works. But it misses a bunch about how the eye works! Cones are not just sensitive to a single color; they have a response curve over a whole range of wavelengths. This means there are pure colors (wavelengths) which produce an eye response outside the span of what can be produced mixing pure red, green, blue light signals. There are other dimensions of complexity to the human biology component: there is a 4th kind of light sensitive cell (rods) that contribute mostly to low-light vision. Some people have fewer kinds of cone cells (color-blindness) or more (tetrachromacy[1]). Eyes are also sensitive to polarization of light [2], which as far as I know has still not entered the display-space discussion. So the color space challenge is about reducing complex infinite-dimensional reality to a small dimension approximation based on limitations of human biology, but using incomplete flawed approximations of that biology. [1] https://www.optimax.co.uk/blog/tetrachromacy-superhuman-vision/ https://www.optimax.co.uk/blog/tetrachromacy-superhuman-visi... [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4528539/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4528539/