Correction of photographs

Let's begin by learning how to adjust basic properties like color, contrast and brightness to correct faults in the original photograph. A word of warning: it is better to under-correct than overcorrect for it is easy to make a photograph look unnatural and worse than the original. If the original photo was badly under-exposed, for example, so that it is so dark that there is no detail in the shadows, then there is nothing you do in the GIMP to bring out detail that simply isn't there! The GIMP can't do miracles!