Sharpen Brush ToolSharpening increases the contrast of neighbouring pixels. The Sharpen Brush Tool gives you full control over the areas that are sharpened and has a cumulative affect. You can easily apply clarity and unsharp mask sharpening selectively with a few strokes of a brush!
The following settings can be adjusted using vertical tool sliders:
Opacity/Accumulation toggle—how see-through the brush is or the extent of deviation in the opacity or visibility of the stroke as it is painted, respectively. Tap to toggle the setting, then slide up or down to set the value.
Flow/Hardness toggle—how fast the brush effect is applied (1% is very slow, 100% is immediate) or how hard edged the brush is, respectively.
Width—controls the width of the stroke using a vertical slider next to the tool's location. Slide up or down to set the width.The following settings can be adjusted from the context toolbar:
Force Pressure—toggle to control brush size with pressure if using a pressure-sensitive device. This overrides brush defaults.The three modes available from the context toolbar have slightly different effects on the underlying pixels.