Mainly used for smoothing skin. It unifies skin’s colors while retaining its structure, so that the edit stays natural-looking. The Intensity setting sets how strong the smoothing is. Detail preservation sets to what extent details are preserved. To erase part of the mask, use Remove from Mask mode 
, which you can switch to in the Brush Parameters group. The brush parameters can be forced to be the same in both modes, or allowed to be different – to change this, use Shared Brush Settings 
. The Diameter, Opacity, Density, and Blur settings work similarly as they do for the retouching tools.
After choosing a mask, use the slider here to set its intensity in the range from 0 to 100 percent.