The Fragment blur will create fragments of your image in small chunks based on a value of your choice and then zoom these fragments with another value of your choice:

As shown in the dialog box in the preceding screenshot, Fragment Count is the number of fragments that will be created, and the Distance is the value of how far these fragments will be placed. Rotation is the direction in which these copies will be moved.

Gaussian Blur is probably going to be your go-to blur effect if you want to add a simple blur to a layer or an image. It can come in handy if you just want to soften an image a little or use it around a background to bring more attention to your subject.

Use a Gaussian Blur effect with the Lasso tool to create a false depth of field. Radius determines the amount of blur applied to your image.

Motion Blur will take a perfectly fine in-focus image and turn it into an image that looks like you snapped it out of a moving car. If used carefully, it can make your image come alive with action.

The Radial Blur effect will be very handy if you wish to create a blur around a person or object while keeping your subject in focus. This is an incredibly handy tool for to create a point of focus or a vignette. What this will do is draw attention to your subject in a very unique way.

Radial Blur has three controls: Angle, Center, and Quality.

The Center control, as shown in the following screenshot, will pop up in a few of the effects explained later and is really easy to understand.

The Center control works on an X/Y grid. By moving the levers, you can center the + symbol on the section of the image where you would like your blur to originate. Keep in mind that if you are working with a large image, it may take some time to render the image completely. Keep an eye on the bottom-right of the Project window, and you will be able to see how the rendering process is progressing.

The Surface Blur effect will put a very thin blur over the entire image. This will give your image a "soft focus" effect. This comes in very handy to soften an image. If your subject has wrinkly, leathered skin, this simple effect is the equivalent of a face lift. It smoothes out wrinkles and hard lines and makes the image softer. This is a technique that has been used since the time that films were used, and is achieved by smearing petroleum jelly on the lens. Now you can achieve it by hitting a button and save your lens from the smears!

Surface Blur consists of two controls: Radius and Threshold:

Radius, which has a value between 1 and 100, represents the size of the area you would like to blur, 1 being the least and 100 being the most. Think of this as a shutter closing around the center of the image.

Threshold also has a value between 1 and 100. This represents the amount of blur you wish to add. The higher the number, the more blur you will add. Adding too much may make your image look smeary, but with the right combination of Radius and Threshold, it can really give someone a glamorous look.

Unfocus does exactly what its name implies; it makes a focused image lose focus at a certain point. This may come in handy if you wish to blur out a background while working with layers. Unfocus has a value between 1 and 200, 200 giving you the maximum blur:

Zoom Blur works just like Radial Blur and is a really good standby for creating vignettes. While Radial Blur makes an image look like the outer edges have been spun, Zoom Blur makes it look as if you were zooming into the subject when the photo was taken. This makes the area around your subject blurry, keeping the center in focus.

Zoom Blur has two controls: Zoom Amount and Center. Zoom Amount has a value between 0 and 100. The higher the number you select, the more it will appear blurred around the edges. Center, like Radial Zoom, will allow you to choose where you wish the point of focus to be. The radius cannot be controlled and hence your may be limited. For instance, if you have a close-up of someone's face, you may find that your subject's eyes are in focus while the mouth may be out of focus. This may end up giving you the effect you want, depending on your intention, but using Radial Blur may be better as you can control the radius with it.