Recently, reader Rod Sawyer wrote to us for advice: He’d seen commercials and music videos in which a subject is in sharp focus and surrounded by an area of blur, and wanted to know how it could be done. He liked the effect for the way it makes the subject stand out and for the dramatic illusion of depth.

It’s fairly simple to achieve this look, especially if you have Adobe Photoshop, and as long as you choose to work on the right kind of picture. In order to create the illusion of depth, you need a picture that has a clear foreground, middleground, and background. Try the effect on a flat-looking picture, and the blur will look like an odd Photoshop trick, rather than an almost-realistic one.

Even though this kind of highly selective blur isn’t one you could get with an ordinary lens, or even a special tilt-shift lens, sometimes it’s fun to use Photoshop to make a kind of picture that would be difficult to make in a camera.

Step 1: This method for making blur uses two layers: the original, sharp image on the bottom, and another layer on top that you’ll blur completely. To create the layer that you’ll add the blur to, duplicate the Background Layer. Go to Layer > Duplicate Layer and click OK, or just drag the Background Layer down to the New Layer button in your Layers panel.