Thumb through any magazine and you'll find that, no matter the style of the photo, all portraits have one thing in common: The background is gently blurred, leaving the subject in sharp focus and the centre of attention. See the accompanying slideshow to see how each step is done.
The traditional way to get this effect is to set the camera's aperture to a fairly wide-open position, corresponding to a small f/stop number. Small f/stops tend to deliver a shallow depth of field so that only the subject that you focus the camera on is sharply focused, and everything else in front and behind tends to blur.
This week, though, let's look at how to get the same effect using Adobe Photoshop Elements 6.
Isolate the subject
Ready to get started? Find a photo with a prominent subject — a portrait like this photo of my daughter should work quite nicely.
Our goal is to selectively blur the background in this photo, while keeping the subject — the girl and the rocks she's standing on — in sharp focus. To do that, grab a selection tool. I like the Magnetic Lasso, which lives in the sixth cubby from the top of the toolbar on the left side of the screen. The Magnetic Lasso tends to snap onto the edges of an object as you move it around the screen, so click on a part of the subject and then carefully start tracing it with the mouse pointer, letting the lasso lock on as you go. There's no need to click as you move, unless you find the lasso trying to snap onto the wrong part of the image. Then you can click to set a keypoint, which tells the tool where to go.
If the Magnetic Lasso goes awry and snaps onto a point that's not an edge of your subject, there's no need to cancel the selection and start over. Press the Delete key — that will remove the last point the lasso locked onto. Work your way around, and when you're done, double-click when you get back to where you started.
Fine-tune the selection
If you need to make any "holes" in your selection — such as where someone's arms or legs part and the background is included in the selection — click the "Subtract from selection" button in the toolbar at the top of the screen (it's the third shape at the left edge of the screen) and then trace around the part of the selection that you want to exclude.
Finally, it's probably a good idea to "feather" the selection, so the edge between sharp and blur won't seem as abrupt and artificial. To do that, choose Select, Feather from the menu and set the effect to about 10 pixels. You'll want to experiment with this value and vary it depending upon the resolution of your photo.
Blur the scene
Of course, we've spent all this time selecting the subject, while what we're really interested in is the background. Let's invert the selection: Choose Select, Inverse from the menu. If you look carefully, you'll see the selection lines change in a subtle way.
Now it's time to blur the background. Choose Filter, Blur, Gaussian Blur from the menu. As you slide the Radius control, you can see the blur effect change your photo. For this particular image, a blur of about 2.0 looks good to me.