Hi all, and Serif's moderator MEB.
Firstly I'd like to reiterate the need for selective colour control w/fine tuning capabilities.
Secondly, my suggestion is further to PS's capability in this sphere, namely: the tools to mask a selective range (eg the yellows/oranges of sunflowers) using a colour picker & range slider (to widen or narrow the colour mask's selection range); and, thereafter, fine tune (say) yellows etc by affecting their complimentary colours (eg blues etc), via desaturation of the highlights&midtones - but only within the selected colour range mask - using (crucially) curves, as well as optional sliders, to effect this example of full tonal control.
The mask allows other yellows/oranges in the photo to be masked/brushed out, and so left unaffected by the adjustments.
I should note I've been taught how to do this on PS, and have been looking to achieve the same with A4iPad - which lead me to this feature request.
kindest regards... M