When I took my original photograph (above), the background was in sharp focus—too much so, in my opinion—making it very distracting. A blurred background is a better choice because it makes the main subject stand out. I could have used a different aperture to blur the background when I took this shot, but I can still get the same effect in the digital darkroom. Here's the Photoshop technique I use, but you can apply the basic principles in other digital darkroom programs.
First, use the Quick Selection tool and select the main subject. Then, invert the selection. Next, choose the Gaussian Blur filter, and then choose the amount of blur you want to apply to your background. When it comes to subject elements such as whiskers, most likely you'll need to paint them back in using the History Brush. Another option for restoring the whiskers is to duplicate the layer before you start your blurring. Once you've done your blurring, use the Eraser tool over the whiskers.
There are also specialized applications for this purpose, like Bokeh from Alien Skin (www.alienskin.com). This plug-in lets you blur the background selectively, quickly and easily.
Sometimes we don't want to blur the background, but refine it in other ways. We can control the brightness level and color of the background, among other enhancements. Here are a few examples.
1.Here's my original shot. I like the brightness, but I changed it in the following examples to illustrate a few points.
Here are three screenshots that show the technique I used. First, I made a new Curves Adjustment Layer. Then, I simply pulled the curve "up" to make the background brighter or pulled the curve "down" to make the background darker. Once I was pleased with the brightness level of the background, I painted out the effect in the Layer Mask (the blue layer above the original layer).
If you're new to Adjustment Layers and Layer Masks, in order to paint out an effect, you need to choose black as the foreground color in the Color Picker (at the bottom of the toolbar), and then choose a Brush to paint out the effect in the white area of the Adjustment Layer. Your "painting out" is shown in black. If you make a mistake and paint out too much of an area, you can change the foreground color to White (hit the X key on your keyboard) and paint over that area. Black paints in; white paints out.
2.Here's the result of making the background darker. As you can see, the subject stands out more in this image than in my original photograph.
3.The background is brighter than in my original photograph. I'm not crazy about the use of the effect here, but you may want to use this technique if you need to or want to see the background more clearly.
4.You see this technique in fashion magazines. The subject is in color and the background is in black-and-white.
Here, I created a black-and-white Adjustment Layer and painted out the effect on the subject.
5.A black-and-white background can be effective, but experiment with this idea: Tint the background, as I did for this image, to add just a bit of color to that area of your image.
Rick Sammon says, "My specialty is not specializing." See why on his website at www.ricksammon.info.