GIMP Plugin Registry

Highpass sharpening script (this is my first script for Gimp).
This technique is described by Rolf Steinort in episode 164 of the Meet the Gimp! video podcast.
You can run it from: Filters -> SkYNeT -> Enhance -> High Pass Sharpening
Because script makes a new layer from visible, make sure you have visible only layer you wish to sharpen. Other layers must be non visible.

The wavelet sharpen plugin enhances apparent sharpness of an image by increasing contrast in high frequency space. The amount of unsharpness of the original image can be taken into account by adjusting the sharpening radius. As an option you can choose to sharpen the luminance (YCbCr) channel of the image only.  read more »