Quick colour balance RGB question

Hello,
Thanks to the developers for the new colour balance rgb module. I am currently testing/discovering it.
I have a quick question :
I would like to neutralise the darker tone in an image (tree trunks that are a bit on the blue/purple side). With a colour picker I made a patch and would like to add a shadow lift. To find the opposite hue, if I understand things correctly, I subtract 180° from the hue found on the color picker. I think I should take the hue from the colour picker in LCh mode but the HSL gives me a hue too.
Am I correct in taking the hue from LCh (I am using the rec2020 working space in scene referred mode) ?

Thanks,
Nicolas

I’m not in my PC now, but I think that this didn’t change from the previous color balance module.
In the 4 ways tab, you have one color picker on each. If you use one of them, it selects you just the opposite color. I will put some captures in the evening if it’s not clear

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Picker in the module is offset 180 by default. So it negates a cast. If you add or subtract 180 you actually have the hue of your cast…That is actually a good way then to boost that color say in midtones or whatever if that is needed.

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The color space used for mapping the color balance RGB GUI with its internal RGB parameters is not HSL, nor Lch, but a kind of Yuv (Yrg) turned into polar coordinates, so the hue angles don’t match HSL nor Lch.

The reason is that Yrg space has a much more even repartition of Munsell hues in the linear space, meaning red, yellow, green, cyan, blue and magenta all take about 1/6th of the hue range, which is really not the case if you look at an HSL hue gradient (green swallows like 1/4, cyan barely 1/10th).

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Thanks Aurélien, love the new filmic v5 by the way!
Pity I can’t access the angle with the colour picker then, I’ll look at the angle in HSL or Lch and eyeball it then!

You have built-in color pickers in the module, though, for each hue. They automatically set the hue slider to the opponent color of the picked area.

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Ah, ok ! Thanks.