Unsharp Mask

The Unsharp Mask live effect sharpens the edges in images. It is not particularly useful for vector objects. Unsharp Mask (also called USM) was originally a photography darkroom effect that combined a slightly blurry (unsharp) version of an image with the original. This results in sharp details in high-contrast areas (such as edges) and minimal changes in low-contrast areas (such as smooth gradients).

You can control how Unsharp Mask applies to an image with its three settings: Radius, Amount, and Threshold.

• Radius  The Radius setting controls the width of the sharpening effect. Too high of a radius causes halos around edges. A radius of 1 is usually appropriate.
• Amount  The Amount setting is like a volume control; it adjusts how intense or full of contrast the edge sharpening is. The higher the Amount, the more edge pixels will be pushed to white or black.
• Threshold  The Threshold value specifies how many tonal steps apart, on a scale of 0 to 255, adjacent pixels in the image have to be before they are considered an edge (and therefore get sharpened). For example, if you set an image to 10, then a soft edge transition from level 25 to 30 will not be considered an edge and will not be affected by the effect; but a transition from 25 to 40 would get sharpened.

The original image (left) and the image with an Unsharp Mask live effect (right)

For more information about how to apply live effects, see Live effects.