Compositing with Layers
When Photoshop debuted, it did not have layers. In fact, its original purpose was to touch up frames of motion picture and photography film. It was, as its name implied, a photo shop. The purpose was a digital darkroom where photos could be enhanced, color-corrected, and even repaired. Over time, however, people wanted to do more inside of Photoshop, including print advertisements and television broadcast graphics. As people expected Photoshop to do more, Adobe responded with the introduction of layers.