Unsharp

This effect applies a traditional darkroom technique, the so called unsharp mask to every video frame. With different parameter values, this can be used to soften or to sharpen the image. Its parameters are:

Amount
moving the slider to the right makes dark areas get darker and light areas get lighter.
Radius
this slider controls how much blurring is used in the edge-finding stage. The practical effect of this is to specify how large a region is darkened or lightened.
Threshold
this slider controls how big a difference between a pixel in the blurred copy and the original copy is needed before any darkening or lightening will be applied.
Clear
to reset its slider to default without affecting others.

The CINELERRA-GG Community, 2021
https://www.cinelerra-gg.org