Local Adjustments: Inverse tint applied?

I was just playing with using an Auto-mask to change the colour of a marker light from Green to Red using the Hue slider - no problem…

But then I thought, why not see what happens if I adjust the Tint towards Magenta…

Green ???

Any ideas? Or is it that the Tint is being applied to the original colour and completely overpowering the Hue?

Likewise if I change the Colour Temperature; I seem to get the inverse of what I expected…

Now that should really confuse all the boats entering the port :crazy_face:

1 Like

That’s why we need a local adjustment color wheel. Using the current LA sliders is very hit and miss. An LA paint in feature would be useful as well.


1 Like

Look at the white point curve in a colour gamut. Then, hue is a colour wheel, tint an offset othogonal to the y-b line, mix it together and voilà, there you are…

I’m sorry but could you please explain that in English? I might be a photographer and software engineer but, for me, colour science finishes at WB or twiddling stuff in PL until it looks right. :wink:

Temperatute/Tint Sliders

  • Let’s look at the Planckian locus first:

  • In the model of the black body radiator (something that emits, but does not reflect electromagnetic radiation, light), that radiator will glow red at low temperatures and bluish white at high temperatures. The emitted light has a colour that can be located in the CIE chromaticity diagram on the curve that we can see in the diagram above.

  • If we move perpendicularly away from the curve (tint, which is relative to colour temperature), colours shift between red and yellow at low temperatures and between cyan and violet at high temperatures (follow the “bristles” in the diagram). Only at daylight temperatures will the tint slider deliver green to magenta shifts.

Hue Slider in LA

  • The hue slider in LA is like the circle in the HSL tool, only cut and straightened.
  • Changing the hue corresponds to a rotation in the HSL circle.

If we now shift several sliders (Temperature, Tint, Hue), we help ourselves with operations in different colour models, which makes colours wander all over the place in a seemingly nonsensical way. Nevertheless, the changes that you saw make sense. Visualise the diagram above plus the hue colour wheel while doing your changes.

Examples: At low temperatures, a full shift (180 degree rotation of the hue wheel) corresponds to a colour change from red to yellow and from violet to cyan at high temperatures.

1 Like

Thanks for ‘some’ insight!

While difficult to ingest (well, digest), it helped me to understand the LA colour tools a little better. :slight_smile:

I find it confusing that the colour adjustment wheel is a circle while sliders usually have a top and low limit - but in the case of the local adjustments you need to think of a cut wheel and ironed to be flat.