Contrast adjustment in RT

Software RawTherapee
13

I totally agree with that. The basic “Contrast” slider, as you noticed, is not extremely efficient, but I think that it was simply not designed for extreme values. I rarely get it out of [-2; 2]. Then, I tweak the Tone curve.

A curve close to a simple diagonal will provide low contrast, while an heavily flexed S-shaped curve will provide a high contrast. By moving the points around, you can choose which tones benefit from the contrast boosts.

I have an ugly video about this, but you can probably find tons of better ones on YouTube: https://alice-mm.github.io/photonotes/images/courbe_lineaire_puis_s.webm

The Tone curve is very powerful and can basically emulate, on its own, many of the sliders from the top of the Exposure tab. A significant proportion of my processing time is spent adding and moving points in that curve. It can generally quickly make the raw look better than the camera-generated embedded JPG, even without fiddling with any other tool.

You might also be interested in:

  • L*a*b* adjustments, as mentioned by others. I generally save it for the end of my processing, though, but maybe there’s no real reason to do so.
  • Increasing both Slope and Power in Color Toning (with the “Color correction regions” method).
  • Local Contrast and Contrast by Detail Levels, even if those are different kinds of contrasts I guess.
  • The abstract profile stuff from Updated August 2025: An alternative method of adjusting tonal contrast & dynamic range in Rawtherapee but it is a bit intimidating at first.
  • In a way, I often end up increasing contrast without really wanting to do so when I use the RGB curves (always in parametric mode, otherwise it’s way too brutal): putting negative values for shadows and positive ones for highlights in there will obviously impact the global contrast. Not really meant for that, but can be nice for color-skewed contrast and stuff.
  • In “Selective Editing”, you can add a “Global” spot with the “Color appearance” tool, which has, in the CAM16 section, both a slider for local contrast and one for contrast, plus stuff for brightness, etc. But I only started using it recently so I can’t tell much more about it. :rofl: I made myself a .pp3 to quickly add that with some not-too-extreme values:

global-cam16.pp3 (5.7 KB)

  • My very last step is often Tone mapping, and it generally increases contrast, in a way, even with a strength of 0.01 (I rarely go beyond 0.2). Actually, it can be so brutal sometimes that I often have to compensate by lowering contrast afterward in other tools.

(NB: I edited this message countless times to add items to the list. Sorry if you got notified too early and read the initial version…)

Why not, if I may ask? When I started using Shadows / Highlights, I hated myself for not having tried it sooner. :rofl:

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