About the Photoshop sharpening filters

Use the Unsharp Mask (USM) filter to sharpen your images. The controls provided by this filter make it the best choice for sharpening. Although Photoshop also has the Sharpen, Sharpen Edges, and Sharpen More filter options, these filters are automatic and do not provide controls and options. You might use these filters for producing creative effects in your image. For more information on the Sharpen filters, see Sharpen filters, and for more information on using the Unsharp Mask filter, see Using the Unsharp Mask filter.

Photoshop lets you sharpen your entire image or sharpen part of your image by using a selection or mask. Since the Unsharp Mask filter can only be applied to one layer at a time, you might need to merge layers or flatten your file to sharpen all image layers in a multilayered file. For more information on sharpening only part of your image, see Selective sharpening.

Note: The name, Unsharp Mask, makes the filter seem like an unintuitive choice for sharpening an image. The term comes from a darkroom technique used in traditional film-based photography. The effect of a sharpened edge can be produced by sandwiching a photographic negative and a slightly blurred and underexposed copy negative in the enlarger. Then the photographic paper is exposed through the sandwiched negatives.