Not All Sharpening Tools Are Created Equal

Photoshop CS3 offers five tools specifically for sharpening: Sharpen, Sharpen Edges, Sharpen More, Smart Sharpen, and Unsharp Mask. These can all be accessed under the Filter -->Sharpen submenu. It’s also possible to use other Photoshop CS3 functions—notably, the Reduce Noise tool, which offers some included sharpening functions, and the use of High Pass, Maximum, and Minimum filters to help control the application of sharpening.

Among the sharpening techniques listed under Filter -->Sharpen, you will want to focus on using Unsharp Mask and Smart Sharpen, because these two methods allow you to control how and where sharpening is applied in an image. When an image is softened  during image capture, the high-contrast portions of the image are softened more than the low-contrast areas. So it makes sense that when you apply sharpening to an image, you will typically want to concentrate the sharpening on the high-contrast edges, while  applying less sharpening to the lower-contrast areas. For instance, when sharpening a close-up image of someone’s face, you will typically want to sharpen the higher-contrast edges, such as the hair, lips, eyes and teeth, while applying less sharpening to the low-contrast areas of the skin. Applying too much sharpening to low-contrast areas can create unwanted mottling in those areas.