I would really love it if this new feature was added. Here's why I think a perceptual color space would be a good addition to the PMCSkin3D editor.

While commonly used across websites and software, the HSV and HSL color spaces are not ideal in artistic applications. In the HSV and HSL color spaces, "Value" and "Lightness" don't actually mean anything in an artistic sense. In HSV or HSL, a yellow with a given value/lightness will appear much lighter than a blue with the same value/lightness. But in a perceptual color space such as HCY', the hue can be changed independently of the luma (value/lightness) or chroma (saturation).

Here, hue and saturation are adjusted while keeping value/lightness/luma constant. Notice how the perceived lightness varies wildly in HSV. HSL gets it a little better, but only in HCY' does the perceived lightness stay constant.



In a color space in which hue (the spectral type of color), saturation/chroma (the intensity of a color) and value/lightness/luma (the perceived brightness of a color) are treated as they are perceived by the human eye, making adjustments to the quality of a color can be done much more intuitively.

For example, let's say that I start off by picking this burnt orange color. Then I decide that I want it to be more of a yellowish hue. It's important to me that the color stays the same perceived lightness. In the HSV and HSL color spaces, if I just adjusted the H alone, it would get lighter, which isn't what I want. I would have to make tiny adjustments in the S and V/L to get it where I want. How much to adjust each value to reach the target color is a skill that needs to be learned, because each color space has its own peculiarities. Novice artists might have some difficulty with this. But in HCY', all I need to do to get the color I want is change the H, and I get a yellowish brown that's the same lightness as the first color.



It also makes selecting color ramps much easier.



Perceptual color spaces include LCH, HSY', and HCY'. More info can be found at the links below. They explain it better than I can.
https://wolthera.info/2014/07/hsi-and-hsy-for-kritas-advanced-colour-selector/
https://lea.verou.me/2020/04/lch-colors-in-css-what-why-and-how/
https://atmos.style/blog/lch-color-space