Using the Unsharp Mask Filter

The Unsharp Mask creates a visually sharper image by locating pixels that differ in value from surrounding pixels. When the filter is applied to the image, the bordering pixels specified by the threshold option get lighter and the darker pixels get darker. It's important to understand that the Unsharp Mask does not actually sharpen the image, it only attempts to create the illusion of sharpness. Be careful, an over application of the this filter creates harsh images with ragged edges and shadows. Also, the effects of the Unsharp Mask filter appear more severe on a monitor with its low resolution, then when the document is output to a printer.