Photoshop Tip: Using Curve Adjustment Layers

PHOTOSHOP TIP: Using Curve Adjustment Layers
by Michael Frye

The Curves adjustment might be the most powerful tool in Photoshop, but it can be tricky to use. Here are a few tips for taming this potent weapon:

First, all PhotoClassroom instructors recommend making a Curves adjustment layer. Instead of going to Image > Adjustments > Curves, go to Layer > New Adjustment Layer > Curves. Or click on the New Adjustment Layer icon at the bottom of the Layers Palette; it's that little circle that's half black and half white:

Then select Curves from the pop-up list.

Once the Curves dialog box is open, Option-click (Windows: Alt-click) to change the grid from this:

To this:

The Curves basics are quite intuitive: you click on the curve to place points, and then you move those points up (or left) to lighten, and down (or right) to darken. Sometimes it's hard to move these points precisely with the mouse, so use the keyboard instead: Command-click (Windows: Control-click) anywhere in the image to place a point on the curve. In other words, if you want a point for the value of the sky, Command-click on the sky.

Press Control-Tab to select the next point up on the curve. Press Shift-Control-Tab to select the next point down on the curve. This helps to select points without accidentally moving them. When a point is selected, press Delete (or Backspace) to remove it. Or just drag it off the grid.
With a point selected, you can move it up, down, left, or right by using the arrow keys. This is great for small, precise adjustments.

Press Command-Z (Windows: Control-Z) to undo the last move you made. Press Command-Z again to redo the last move. With Preview checked, this lets you toggle back and forth to decide which version you like better. (This also works in most other Photoshop dialog boxes: Curves, Levels, Hue/Saturation, Unsharp Mask, etc.)

If you want to start over, hold down the Option key (Windows: Alt key) to change the Cancel button to a Reset button. (Again, this works in most Photoshop dialog boxes.)

When you've made the modifications you want, click OK to accept those changes and create the Adjustment Layer. If you decide later that you don't like what you did, just double-click on the Layer Thumbnail on the Layers Palette to re-open the Curves dialog box: