I find that the easiest way to separate Chroma and Luma to operate on each independently is to change to Lab mode and adjust there....very obvious to see and use adjustments and to easily check on the accuracy of colors for skin tones, foliage, skies, etc.; especially when compared to checking colors in RGB with Luma built-in to the color numbers. There are charts to explain what Lab color numbers are "correct" for real life objects.
I find that the easiest way to separate Chroma and Luma to operate on each independently is to change to Lab mode and adjust there....very obvious to see and use adjustments and to easily check on the accuracy of colors for skin tones, foliage, skies, etc.; especially when compared to checking colors in RGB with Luma built-in to the color numbers. There are charts to explain what Lab color numbers are "correct" for real life objects.
I'll have to check that out, I haven't worked in Lab mode a whole lot in *years*. Thanks!