by Emil Sohlberg
As studios ramped up the production of live-action features, hand-drawn animation underwent a similar revolution with the invention of cel animation. Cel animation was defined by the division of an animated shot onto different transparent celluloids, which could then be overlaid. With this technique, a background, which previously would have been redrawn for every frame, could be reused for a scene, while just the cels that contained the movements of characters would be updated. Even moving characters could be split into different cels; after all, if the only moving part of a character was their face, then their body could be reused if on a separate sheet of celluloid. While inherently cost- and labor-saving, cel animation also allowed for a natural specialization in the animation process, where different animators could work on the same scene simultaneously by splitting that scene’s cels, with some working on backgrounds, or on character poses, and so on.