Project #24 - Sharpening Blurred Photographs

Occasionally we all take photographs that are blurred due to camera shake, or by pressing the shutter release before the camera has stopped focusing. With the aid the three Sharpen filters within Adobe Photoshop (Sharpen, Sharpen Edges, and Unsharp Mask), the blur can be reduced and the photograph saved from the rubbish head. Sharpening an image should only be performed after any other editing and color correction. Have a read through this tutorial and see which filter suits you best Remember though, you cannot make a silk purse out of a sows ear! If the original photograph is too blurred, then no end of sharpening will not help it. This technique works better with slightly blurred/out of focus photographs.   To remove the chance of camera shake, mount your camera on a tripod as much as possible. If you don't have a tripod - try resting the camera on something solid, such as a wall, or fence post. Oddly as it sounds, a small bean bag will help you keep the camera steady too!

1. Using the Sharpen Filter [Filter... Sharpen... Sharpen]

   Once the image has been imported into Photoshop, select the Sharpen filter. At first you may not notice any difference, so press CTRL+F to run the filter again. This may need to be repeated several times until the desired sharpness is achieved.

   If the sharpness is too pronounced, use the Fade command [Filter... Fade...]. Here, you can lessen the opacity (intensity) of the last filter by moving the slider towards the left. Alternatively, try selecting and option from the Mode drop down menu (try various options to see their effect).

2. Using the Sharpen Edges Filter [Filter... Sharpen... Sharpen Edges]

   The Sharpen Edges filter attempts, as its name suggests, to sharpen the edges of the image. On the example I used here, it was necessary to adjust the opacity (intensity) of the filter using the Fade Last Filter command [Filter... Fade...], quite a bit after using the Sharpen Edges filter. In most cases it appears better to use the Unsharp filter.

3. Using the Unsharp Mask filter [Filter... Sharpen... Unsharp Mask...]

   This filter is the king of the Sharpen filter. It is the only one that allows you to adjust the setting manually (rather than taking over the process) giving you more control. Once activated, the filter presents you with a dialogue box with three adjustable settings.

   Radius defines the distance the filter affects and is the first setting to be adjusted. A radius of 1 changes 4 pixels, each addition to the radius affects a further 4 pixels. To determine the starting point, take the dpi (dots per inch) of the image and divide it by 200, eg an image of 300dpi would have a radius value of 1.5. If the value is too small, the unsharp masking is not effective. If its too large a 'halo' effects appears. Adjust the radius value until the desired effect is reached.

   Amount controls the change in the contrast along the edges. A high value causes the edges to brighten - and a low value darkens the edges. As the amount is increased, the radius needs to be decreased so the degree of sharpening is constant. A good Amount setting would be somewhere around the 200 mark.

   Threshold determines the values included in the edge finding process. If the value is set to 0, all the values within the images are included resulting in an edge being found everywhere - this can create edges in clouds, skin tones etc, when they should be smooth. The value should be set somewhere between 4 and 10; too high a value and nothing happens.