For a lot of Photoshop users, blur tends to mean just one thing – that is Gaussian Blur. The other blur filters, “Blur” and “Blur More” have been part of Photoshop for a long time, but they generally require that you use the filter repeatedly before you start seeing the effects you’re after.
The Radial and Motion Radial Blurs have their uses when it comes to some special effects and like the Gaussian Blur filter, they have a preview window and a slider which allows you to control the strength of the blur. Even still, many of us rely heavily on the Gaussian Blur filter for our heavy-duty blurring.
However, there are two other blurring filters that are well worth taking a look at. They are the Smart Blur and the Lens Blur which have been added in more recent versions of Photoshop.
The Smart Blur blurs the image with great accuracy. Like some of the other blurs, you can stipulate a Radius which determines the degree of blurring applied. You can also specify the Threshold value. This stipulates how unalike the pixels must be before they are blurred. The third value that you can set is the Blur Quality. The choice here is low, medium or high quality. The final option available with Smart Blur is to set a mode for the entire selection ( Normal) or for the edges of color transitions (Edge Only and Overlay). This is where you can get some really interesting and perhaps somewhat unexpected effects for a blur tool. Where considerable contrast occurs between the edges, Edge Only applies black-and-white edges, and Overlay Edge applies white.
Open up an image in Photoshop and try this one out. To get to this filter, choose Filter > Blur > Smart Blur. Set the mode to Edge Only to get an effect like the one below.
There is, of course, much more to the Smart Blur than creating white outlines, but this is a good place to start playing. In the next part I’m going to take a look at the Lens Blur in Photoshop.