Contrast in the midtones: clarity, local contrast, wavelet contast, haze removal, etc.

When I was a LR user, I enjoyed (rather mindlessly) using the clarity slider to increase contrast (and hence also sharpeness) in the midtones. Now that I have been a RT user for a few years, I notice that there is a plethora of options for accomplishing–broadly–the same thing. It appears that local contrast, haze removal, and wavelet contrast do pretty much the same thing. Is this correct, or am I missing something?

I am a cautious user of these types of things–for two reasons. First, I find that many photos I see online are oversaturated, oversharpened, and overly contrasty. Second, I don’t mind shooting in overcast and even rainy conditions (I love rain!!) and you don’t get that type of high contrast and saturation under those conditions. I err on the side of caution in applying these adjustments!

Anyway, I would be interested to learn which of these (or other) midtone contrast adjustments users prefer and use, especially in RawTherapee. What to you use, how, and how is it integrated into your workflow? Please enlighten me.

(Moved to the RawTherapee category for better visibility.)

local contrast:

haze removal:

wavelet contrast:

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The Contrast by Detail Levels transformation is the finest tool for local contrast I’ve found in half a dozen post-processing programs. But I don’t know how to confine it to a midtone range.

The basic tool to adjust tonal contrast is Curves, found in most editors. For mid-tones, contrast is increased by an S-shaped curve centered in the middle. Mid-tone contrast is increased but at the expense of light and shadow contrasts.


It helps to think about contrast in two broad categories: tonal, and spacial.

The tone curve and contrast are tonal, they pushe pixels closer or further that are separated by tone: bright things get brighter, dark things get darker (or vice versa), uniformly, everywhere in the image.

Clarity and its ilk are spacial. They push neighboring pixels closer or further. Edges get edgier, but smooth gradients get flattened (or vice versa). This happens locally, but bright regions remain bright on average, and dark regions remain dark on average. It behaves somewhat like a very coarse sharpening.

So I tend to think about what I want to do. Do I want to change tonal relationships between areas? Or do I want to preserve relationships, but emphasize their internal punch?


Contrast By Detail Levels allows the User to change contrast based on detail size but not based on tonal level. That is to say that CBDL can be applied to, say, 8-pixel size details whether they are in the high, mid or low tonal ranges.

You can use the local adjustments version of the tool to to do this. As this feature can take some time to learn, here is a step-by-step

  1. Enable local adjustments
  2. Click [Add]
  3. Under the Spot Method dropdown select “Full image”
  4. Place the spot on a midtone somewhere in the image.
  5. Click the “Add tool to current spot” dropdown and select “Contrast by Detail Levels”
  6. Enjoy :partying_face:

Another way if you have the GIMP is to use the Wavelet processing function where any adjustment in the GIMP can be applied to any one wavelet Level.

For example, I selected level 4, set a curve to mid-tones only then applied a magenta color-cast:

Thank you. Makes a good introduction to using Local Adjustments.

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