By following this tutorial, you will be able to create a grungestract background using nothing but GIMP’s standard filters; no brushing and no additional scripts or plug-ins. Furthermore, each step of this tutorial will be explained fully, complete with as many screenshots as there needs to be.
Short tutorial about selective decolorization using The Gimp image editor. In other words: You will learn how to change certain objects of a colored image into black and white.