Tutorial: Sharpening

Unsharp Mask Sharpening:

Probably the simplest of all the Photoshop sharpening tools.

Original Image at 100%

After Unsharp Mask Sharpening at an Amount of 1 and a Radius of 100. This looks about right.

An Amount of 300 just to illustrate the effects of over sharpening an image.

Note the slight halo effect along the edges, particularly dark edges and the increase in Noise grain. This is over sharpened.