Traditional animation, also known as cel animation, was the process used for most animated films of the 20th century. The individual frames of a traditionally animated film are photographs of drawings, which are first drawn on paper. To create the illusion of movement, each drawing differs slightly from the one before it. The animators’ drawings are traced or photocopied onto transparent acetate sheets called cels, (from where the phrase ‘cel animation’ has been dervied) which are filled in with paints in assigned colors or tones on the side opposite the line drawings. The completed character cels are photographed one-by-one onto motion picture film against a painted background by a rostrum camera.
This process became obsolete by the beginning of the 21st century. Today, animators’ drawings and the backgrounds are either scanned into or drawn directly into a computer system. Various software programs are used to color the drawings and simulate camera movement and effects. The final animated piece is output to one of several delivery mediums, including traditional 35 mm film and newer media such as digital video.
Full animation refers to the process of producing high-quality traditionally animated films, which regularly use detailed drawings and plausible movement. Films produced by Walt Disney studios are full animation films.
Limited animation involves the use of less detailed and/or more stylized drawings and methods of movement. Pioneered by the artists at the American studio United Productions of America, limited animation can be used as a method of stylized artistic expression. The Hannah Barbera cartoons are examples of limited animation.
Rotoscoping is a technique, patented by Max Fleischer in 1917, where animators trace live-action movement, frame by frame. The source film can be directly copyed from actors’ outlines into animated drawings, as in The Lord of the Rings (US, 1978), used as a basis and inspiration for character animation, as in most Disney films, or used in a stylized and expressive manner, as in Waking Life (US, 2001) and A Scanner Darkly (film) (US, 2006).