How to avoid color shifts with Lightroom curves

Adobe Lightroom (LR) and Adobe Camera RAW (ACR) recently added a very powerful but mostly overlooked feature: “refine saturation” (or just “refine” in ACR). You’re probably well aware of the luminosity blend mode for layers in Photoshop and how it can often be useful to avoid unwanted shifts in color when making adjustments. The same problem affects LR / ACR and this new slider gives us a way to help manage it.

How does refine saturation work?

  • When you increase contrast with a point curve, colors get more saturated (hue may also shift somewhat).
  • When you decrease contrast with a point curve, colors start to desaturate (hue may also shift somewhat).
  • In either case, adjusting the refine slider down will offset those changes. Dragging it down is therefore a lot like the luminosity blend mode in Photoshop, but with the full range of a slider instead of only offering one extreme or the other.
  • The refine slider has no impact on gray pixels (and won’t even be available if the image is fully black and white).

You’re much more likely to be using a curve to add contrast, so most of the time it would seem that the refine slider desaturates the image – but it really depends on the curve.

This refine slider is available for both global and local adjustments. However, it is only available for the point curve, not the parametric one with sliders (you can create a similar point curve though) or the R,G,B curves (which are intended for color adjustment).

What are the best ways to use refine saturation?

  • Any time you see unwanted saturation or hue shift with a curve, it is worth adjusting the slider to see if you get improved results.
  • Contrast boosts on skin tones or highly saturated colors are especially important cases, as boosting saturation further in either is typically unwanted.
  • If the “contrast” slider shows unwanted color shifts, try using an S-curve and its refine slider instead.
  • If you need to make tonal adjustments for highlights / shadows, you can use a local adjustment based on a luminance range and then use a local curve with refine slider.

Note that just like luminosity blend mode in PS, the refine slider may affect apparent luminosity of shadows and may not hold the hue visually constant. It helps quite a bit to try intermediate slider values to find the optimal results, and you may wish to make small tweaks to the curve after big moves in the refine slider.

Greg Benz Photography