Quickly lighten or darken your images using the Levels command (CS2/CS3/CS4/CS5)

The Photoshop Levels command creates a lot of unnecessary anxiety in many users. The reality is that you don’t have to fully understand everything about it to reap its benefits. For example, have you ever had to lighten or darken an image? Well, a simple way to do this is to adjust the image’s Input Levels. To see how it works, open an image in Photoshop. Next, press [command]L ([Ctrl]L in Windows) to access the Levels dialog box. To lighten the image, drag the white Input Levels slider toward the left. To darken the image, drag the black Input Levels slider toward the left.

Another approach, which produces slightly different results, is to adjust the image’s Output Levels. To lighten the image, drag the black Output Levels slider toward the right. To darken the image, drag the white Output Levels slider toward the left.

Whichever way you choose—when you're happy with the results, click OK. That's all there is to it!