You can make basic tonal adjustments with levels and more sophisticated modifications with curves, but the Tonal Contrast filter in DxO Color Efex Pro goes a whole step further.
The problem with curves adjustments is that any change you make in one area of the image curve has a knock-on effect on the rest. If you boost the midtone contrast by steepening the curve, for example, this flattens out the highlight and shadow areas.
But the Tonal Contrast filter in Color Efex Pro lets you confine your adjustments to the Shadows, Midtones or Highlights only. If you just try out the presets, you could get the idea that this filter is for creating faux HDR effects, but the reality is quite different. If you start from scratch and use your own settings, you can achieve tonal improvements than curves alone can’t provide.
Here’s my start shot. It’s OK as it is, but the textures in the stone walls and pillars are quite weak. I’d like to be able to inject some contrast into these areas, without substantially increasing the overall contrast, which is high enough already.
01 Reset to zero
What I’m going to do, then, is select the Tonal Contrast filter from the list on the left, then manually reset all the sliders in the tools panel on the right to zero. (If you find yourself doing this a lot, you could save time in future by creating a new ‘zero’ preset.)
02 Highlights adjustment
Now I want to show how this filter targets specific tonal ranges, and I’ll start by pushing the Highlights slider right up to maximum. This applies a contrast increase to the highlights only – but as you can probably see, there are no real highlight areas in this image at all – it’s mostly midtones and shadows – so this adjustment has no visible effect.