Curves are one of the more mystifying tools available in the photo editing world, in appearance anyway. With so many simpler looking ways to make changes to your photos, it’s easy to gloss over the one that isn’t self-explanatory. In Lightroom, sliders are no problem. Just slide right or left and watch what happens to your image – easy.
But that Tone Curve tool, with its diagonal line across a box and all the points you can add, is a little harder to comprehend. If you start adding points and making changes at random, your image will morph into some bizarre creation.
But, allowing intimidation to keep you from exploring will get you nowhere. The concept of the tone curve is actually more straightforward than it seems. If you look closely, you’ll see that the tone curve’s box contains a histogram. This is a clue to what that line and points do.
The left side of the Tone Curve tool represents the darkest tones in the image, the right represents the brightest tones, and in the middle are the mid-tones. By clicking the diagonal line and creating a point, you can drag the corresponding tones up or down to brighten or darken the image wherever those tones live.
A beneficial application that visually teaches you exactly what the tone curve is doing is to take a white to black gradient into Lightroom and use the sliders. YouTuber Lucy Martin has made a video offering a succinct explanation of how Lightroom’s Tone Curve works that demonstrates this, as well as the Tone Curve applied to real photographs.
The most common way to use curves in photography adds a quick pop of contrast using an “s-curve.” By making three evenly spaced points in the curve and dragging the shadows down a little and the highlights up a little, contrast is boosted in a way that gives you more control than by using the Contrast slider.
It’s worth noting, to fully utilize the Tone Curve’s features and add points, you have to click the little button in the bottom right corner of the tool. This toggles between a slider-based tone curve and one you can fully adjust.
Lucy goes a bit deeper in her explanation and includes information on changing colors with the Tone Curve tool while still keeping her tutorial short and to-the-point. Check out her video below to learn how to use the Tone Curve in Lightroom to improve your images.