A simple node group which can be used to apply a sharpening or softening filter to an image in compositing. The group is called "Sharpen/Soften".
The radius input controls the thickness of the lines and softened edges. The Strength input controls how sharp or soft to make the image. Negative values soften the image, and positive values sharpen the image. Softening the image will blur out some noise, and sharpening will increase the contrast of noise.
The two images shown are extreme examples of the group's effect. In the softened image, the radius is set to 1 and the strength to -15. In the sharpened image the radius is again set to 1 and the strength to 25.
THIS BLEND IS PUBLIC DOMAIN. Take a look at the last image to see how this simple node group works, so you can incorporate it into your own projects.