Sharpen filters manipulate the contrast of clips and can result in an image that has more detail if used sparingly.
Sharpen increases the contrast between adjacent pixels, increasing the image's sharpness. Pushing it too far can create a grainy look.
Unsharp Mask actually is used for sharpening. This filter increases the contrast of adjacent pixels with greater control than the Sharpen filter. With individual sliders, you can adjust the amount, radius, and threshold of sharpness to soften this filter's effect. The Luminosity check box adds some luminance to the effect.
