Hewlett-Packard's Linux imaging and printing software
The Hewlett-Packard Linux Imaging and Printing Project provides a unified single and multi-function connectivity solution for Linux. For support and help, please visit https://launchpad.net/hplip
A Gimp plugin that implements the Octave Sharpening method
Octave sharpening is a plugin for The Gimp that implements a method which produces intense sharpened images without halos or noise.
If a High Pass Filter is not enough, try this.
Simulate HDR is a plugin for The GIMP that creates two layers from a single image simulating an underexposed and a overexposed shots, creating a High Dynamic Range image.
It can create a tone mapping layer to compress the color range of the image.