...by blurring the background, yet keeping the grain.
You can remove distracting detail from an image or focus attention on the subject by isolating the subject and keeping it in focus as you blur other parts of the picture. The Photoshop technique presented in this tip imitates the effect you get with a shortened depth of field, traditionally achieved by opening up the camera's iris (setting the f-stop low). The blurring can be limited to the background, or, as shown here, the sharp subject can be sandwiched between blurred background and blurred foreground. In either case, you'll need to make the blurred areas match the sharp ones by restoring the film grain or digital noise (the equivalent of film grain in an image captured with a digital camera) that was lost in the process of blurring.
Defining the Foreground
If you want to keep a foreground subject in focus while blurring only the background, it's a good idea to make sure the foreground subject bleeds off the bottom of the picture, even if it means cropping the image. Otherwise, if the subject is standing on the ground, it can be very tricky to make the transition from the in-focus ground at the feet of the subject to the out-of-focus background.