Cel animation, also known as traditional animation, is a technique where each frame is drawn and characters painted by hand on transparent sheets of celluloid (cels for short). The process was time-consuming and costly, requiring a large team of artists.
Cel animation starts with the lineart being done on one side of a blank cel with ink. (In later years, Xerox photocopiers replaced hand inking, except for colored lines.) The cel is then flipped over, and a painter colours it in from the other side. Backgrounds are created separately. When both are complete, the cel is stacked in front of the background. It is photographed, creating a frame. More cels are painted and photographed in sequence to create the illusion of movement.
This technique was the main way of producing animation during the 20th century, especially in The Golden Age of Animation. It was the standard for animated films until the advent of computer animation, such as CGI or 2D programs such as Toonboom Harmony.
Not to be confused with Cel Shading, another type of animation that has nothing to do with cel animation.
The high cost and time consumption of cel animation often resulted in Limited Animation; for instance, reuse of the same frames for several sequences.
