How to Adjust Curves in Photoshop CS6

By Barbara Obermeier

To adjust curves, click at any point on the curve other than the end points and Photoshop CS6 adds a control point that shows your position. You can remove a control point by dragging it downward until it’s completely off the graph or by dragging it on top of the next point up or down from it on the graph. You can add up to 14 points to the curve.

Curve presets are located at the very top of the Curves dialog box. If you’re a Curves novice, trying one of these presets is a good way to get your feet wet in how curves work. When you select a preset, a curve is loaded into your dialog box. You can also use a preset as a starting point and tweak it later. Experiment with the curves first..

  • Click the Auto button to have Photoshop analyze your image’s color and tonal values and make an automatic adjustment. Again, you can use this preset as a starting point and tweak from there.

  • Flattening a curve lowers contrast.

  • Making a curve steeper heightens contrast.

  • Moving a curve downward (if the display is set to Light) darkens the image. Moving it upward lightens.

  • If your display is set to Light, adjust your highlights by moving points in the top-right of the curve, shadows by adjusting points in the bottom-left of the curve, and midtones by moving points in the center of the curve.

  • A gently sloped S-shaped curve increases contrast, especially in the highlight and shadow areas. Using a curve like this also helps to define the midtones.

  • For ultimate control, Photoshop lets you draw a curve with the precise shape you want, creating an arbitrary curve or map. Click the Pencil tool and then draw peaks and valleys in the Curves dialog box. Watch the changes in your original image.

  • You can also add points to the curve by holding down Ctrl (Command on the Mac) and clicking your image. Adding points is beneficial if you want to preserve an area in your image.

  • If you want to adjust the color in your image, select your desired channel from the Channel pop-up menu and then adjust the curve.

Arbitrary maps create distinctive solarization color effects when Photoshop warps the colors of your image. They’re fun to play with, maybe useful now and then, but not nearly as practical as S curves.

[Credit: ©iStockphoto.com/sivarock Image #10926048]

Credit: ©iStockphoto.com/sivarock Image #10926048

After you create a custom curve, you may want to save it (a good idea) to load and apply it to other photos with similar contrast issues. Click the Preset Options button (just to the left of the OK button) and select Save Preset from the pop-up menu that appears.