Digital Light & Color

The Levels and Colour are great, flexible, one-stop, adjustment panel, that doesn't require much learning - especially now, with the contrast slider added to it (thank you!). Even grays can be probed to adjust WB quickly or change the overall colour cast of the image via Colour Picker Options/filters or colour temperature slider. But this affect the image tones globally, including grays.

What would be a good way of changing the colour 'tints/chroma', but leaving neutrals alone. I can think of masking by saturation or using Colour Correction with whites pinned down, but that's pretty complex when you learning your way around the PWP. Would people have a better idea?

I can't find it anymore, but I think I suggested a technique in the past where Colour Correction vectors, placed around the base hexagon, were used to 'twist' the entire HSV hexacone CCL or CL and thus change the 'tint' or 'tone' of all the colours proportional to their HSV-S, but leaving the whites/grays alone. It works, but requires understanding of how Correction transformation works, and even then takes two different pre-prepared .colorcorrect files (one for CCW another for CW turning) and it's not particularly convenient.

Would it be a good idea to implement some similar turning of HSV/HSL cones that will leave grays untouched, as a slider in Levels and Colour? I think it would be quite useful and convenient, especially for PWP learners.

But maybe there is some other, simple way of doing that already, that I can't think of?

Selective Color Correction is the best (and simplest) way to do this currently - I have not found a global hue twist to be a particularly useful as different colors usually require different corrections - you can simulate it with Color Curves and adjusting the Hue and Saturation only.

One potential problem with using Hue curves to shift colours a bit is the discontinuity at Red, on Magenta side. Shifting hue bt twisting the HSV hexacone with Selective Colour Correction, however crude that may be, avoids this issue, I think.

Another way I figured is making a Colour Range mask with S having a smooth gradient from 0 (or higher) to 100 and then shifting colour with Levels and Colour, e.g. Colour Temperature slider, thus protecting the whites/grays. It can also be done in HSL.

I have introduced a friend to Selective Correction, which is certainly great. One word of caution that transpired is that one needs to be somewhat careful not to add too many vectors as it may result in 'tearing' the image at the colour boundaries.

It all can be done, and there is probably a few other ways of doing it in PWP, it's just not that easy to explain at first - people like, smooth, magic sliders...

Just an idea: perhaps an implicit HSL/HSV-S, y=x mask, implemented as e.g. 'protect neutral grays' checkbox next to Levels & Colour's Colour Balance box could work?

That would allow to use all colour shifting methods of Colour Picker, including Filter Banks and Temperature slider, but applied proportionally to saturation, thus protecting grays?

Maciej, maybe I understood you wrong, but isn't a Color / Extract Channel ... HSL (HSV) Saturation extracted channel just exact the mask you are looking for ?

To add to Dieter's suggestion/question... ...perhaps one could skip the HSV-S or HSL-S channel Extract-ion altogether by simply using the Mask Tool - Color Range feature in either HSV or HSL... ...and move the S left white pointer slider to the right approximately 10% the length of the S color bar... ...then lower-left Apply Add to the image.

This would provide a mask of the 10 to 100 percent saturations [mask white] with the 0 to 10% saturations [mask black] protected from Hue changes. An Undo or None; re-position of the left S white pointer slider; and a lower-left Apply Add would increase or decrease the low saturation range adjusting the image's original neutral grays image areas to a preference... ...den...

Dieter: the S channel is the mask - Den's Colour Range is another option. It's just my experience that using masks isn't that conceptually easy at first, so I figured that if Colour Balance in Levels&Colour had a switch (checkbox), optionally weighing colour shifts by HSL(HSV)-S, that could make it even more useful, without taking much real estate or making the transformation much more complicated.