How to Blur Sharp Images in Photoshop CS6
You may find the need to apply a blur filter in Photoshop CS6 if you have an image that contains unwanted grain (the roughness or noise added by the photographic film) or perhaps an ugly pattern of halftone dots used in a printed image.
You might also need to blur a background to make the foreground seem sharper or blur a portion of an image to create an angelic glow. Here are your blurring options (all in the Filter→Blur menu):
Average: This single-step filter calculates the average value (or color) of the image or selection and fills the area with that average value. This option can help you smooth the values of areas that contain a lot of noise.
Blur: Also a single-step filter, Blur provides overall blurring of an image.
Blur More: This filter provides a significantly increased amount of blurring compared to the regular, old-fashioned Blur filter.
Box Blur: The Box Blur filter blurs your image in the shape of, well, a box or square.
Gaussian Blur: This filter offers a radius control to let you adjust the amount of blurring more precisely. It also has a really cool name.
The Gaussian Blur filter is an excellent tool because it gives you a great deal of control over the amount and type of blurring you get, especially when compared to the single-step Blur and Blur More filters, which apply a fixed amount of blur.
Use these latter two filters when you simply want to desharpen an image a tad, and turn to Gaussian Blur when you’re looking for a specific effect.
Lens Blur: This filter simulates the blurring that can occur when you capture an image with a camera.
Motion Blur: This filter simulates the blur you see in objects that are moving.
Radial Blur: This filter produces the kind of blur you might get when photographing a revolving automobile tire. You can also get a zoom effect with this filter.
Shape Blur: The Shape blur basically blurs your image according to the shape you choose from the panel. The shape choices you have are the same as those with the Custom Shape tool. Move the Radius slider to the right for a larger blur.
Smart Blur: This filter lets you control how Photoshop applies the blur to edges and other details of the image.
Surface Blur: This filter blurs the surface or interior of the image, rather than the edges. If you want to preserve your edge details but blur everything else, this is your filter.