Let's say you want to create the look of text painted on a wooden board and you want the text to look like it's been out in the weather for a long while. There are several methods you can use to distress text. You can find some of them on the web by searching for “GIMP text”, plus one of the following words: weathered, distressed, worn.
This tutorial describes how to create the following image using a photo of a gray board, some text, and a photo of a rusty metal texture that is processed and turned into a layer mask. You can download the two photos (Weathered Gray Wood 0099 and Rusty Metal 0817) from the Free Images page of my blog.
GIMP is really useful for adding
special effects to photos and drawings. In this article I'll describe
a simple method for creating lightning bolts that can then be
resized, reoriented, scaled, or otherwise processed to fit into an
image.