The Tone Curve is actually a curve interface that’s easier to use. One of the things that always bugged me about Photoshop’s curve interface was that it wasn’t very intuitive. If you weren’t familiar with it, adding points to a curve could really take your photos on a turn for the worse. With the Tone Curve, Adobe has made the process much more visual. You can’t actually add points by clicking the curve, but you can selectively move specific parts of the curve by using the sliders (see Figure 7). The overall function and details behind what a curve really is haven’t changed, which is nice. The Tone Curve just makes the whole curve editing process easier, as it takes care of smoothing out the curve for you.
Figure 7 The Tone Curve is like Photoshop Curves, but better.