Have you ever tried tiling a texture, only to find that the lighting in the texture image is not uniform? Dark and light areas shows like a pattern throughout the tiles, ruining your image even though your edges might be seamless enough?
Painting these kind of unwanted effects out of textures by hand is a tedious and almost impossible task. This tutorial will show you how to deal with this in a whole different way, easily replicated in most 2D image editors. This method is quite effective and works in a lot of cases.