Blurring might not seem like an obvious technique for improving an image, but it can actually be used constructively in a variety of ways.

If the eye is distracted away from the subject of the image by unnecessary background detail, blurring can be applied effectively. By blurring the background, the subject becomes a stronger element in the composition.

Also, as discussed here, using a high ISO setting in the camera can result in an image with a lot of noise. Blurring, in various forms, can be used to smooth out the slight differences in the image to make a region of colour look more uniform.

Blurring can be such an important technique that programs usually provide a range of tools for the task.

Different Kinds of Blur

Like all image manipulation techniques, behind the scenes blurring is actually a mathematical transformation that is applied to the image. Because there are different ways of doing the blur, there are different techniques that you can try - each gives slightly different results in different circumstances.

In Photoshop you can find the Despeckle tool, intended for removing noise from an image, on the noise filter menu.

You can also find a range of useful tools on the blur filter menu. In the examples discussed below a tool called Gaussian Blur is used as this gives you some control over the final results.

The GIMP also provides a dedicated despeckle tool which can sometimes give acceptable results. You can find this tool on the Filters>Enhance menu. Also, the various blur tools can be found on the Filters>Blur menu.

Practical Examples

You can find a couple of examples showing how to use blurring to emphasize the subject of a picture here...

You can find an example of attempting to use blurring to smooth out digital noise here...



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