HISTORIC IMAGE RETOUCHING
Back in the 19th century, image manipulation was first introduced as retouching. This was a highly skilled and time-consuming job that only the richest of photographers could afford to make slight adjustments to their pictures.
This process remained unchanged for a long time, right at the start of photography regardless of the type of negative. After a negative was exposed, it was processed using chemicals in the darkroom to develop and then fix the resulting image.