"Already, sRGB’s FF0000 is quite definitely on the orange side of neutral (I tend to call the sRGB primaries “orangish red”, “yellowish green”, and “purplish blue” for clarity when trying to explain technical aspects of color to non-experts)."
I did wonder about that, especially when desaturating "pure" blue produced a kind of lilac, and when I got a cyan (rather than green) after-image from "pure" red.
Thanks for confirming.
Out of interest, where would you say neutral red, green and blue fall in the sRGB space (or are they out of gamut)?
For any given hue, you can pick a range of colors. There are an infinite number of neutral red/green/blue/yellow colors within sRGB. However, for blue and green especially, these unfortunately happen to be less colorful than you might achieve with paint or see in nature.
(Note, the “hue” measure used in spaces like HSL/HSV is non-uniform, especially in the blue–purple range. So that explains part of the effect you see when you “desaturate” sRGB #0000FF. Your “desaturate” operation is also shifting the hue, if you define hue based on human perception.)
The lessons from scratchapixel.com were for me the most helpful, they really made all the stuff about colour-spaces "click" for the first time. Mainly this chapter, explaining about the tristimulus, CIExyz and how they transform into sRGB and what is up with that horseshoe shape:
Further, if you click around there's a few more chapters relevant to colours that put this theory into practice (in the context of raytracing and rendering):
I did wonder about that, especially when desaturating "pure" blue produced a kind of lilac, and when I got a cyan (rather than green) after-image from "pure" red.
Thanks for confirming.
Out of interest, where would you say neutral red, green and blue fall in the sRGB space (or are they out of gamut)?