GIMP Plugin Registry

This extension allows you to add dominants to your black and white (or colour) photos.
In the "Layer mask" mode the dominant is balanced with a mask, such that your whites remains whites.
The homepage is in Italian but you can see some screenshots and examples there. Please note also that the plugin is in English.

Before

After

This script converts color images to B&W using channel mixer settings,
which simulate the use of color filters in B&W photography. It allows to choose many predefined filters and set their intensity. Previously posted to old registry in July 2006, now updated to work with GIMP 2.4. Avoid setting intensity to 1, besause it totally filters one of RGB channels and increases noise.