The earliest animations were hand drawn on paper or chalkboards. This required the complete image to be redrawn for each frame.Later animations would be created by drawing images by hand on transparent celluloid (cellulose nitrate) sheets called cels. These cels would later be photographed onto motion-picture film to form the finished animation. The process of cel animation is attributed to Earl Hurd who patented this process in 1914. A few years after the introduction of the technique, the material of the cels was changed to cellulose acetate, as celluloid would burn extremely vigorously when exposed to heat (Wikipedia, 2007f).
Techniques
The use of cels enabled animators to use several techniques which could both improve the quality of animation, and reduce the time required to create an animation.
Limited Animation
Animators would draw backgrounds on one or more cels then add characters and objects on additional cels. This enabled static backgrounds to remain unchanged between frames, dramatically simplifying the process. This was known as limited animation (Wikipedia, 2007f).
This process could be further extended to allow entire scenes to remain static while only the characters mouths moved - this technique was common in the cartoons produced by the Hanna-Barbera company (Scooby Doo, The Flintstones etc.). While this process was extremely fast and cheap, it was not very lifelike.
Animation Loops
Another common use of limited animation involved creating animation loops - where a short sequence of animation would be repeated to create longer sequences - for example a person walking or a background scrolling past characters (Atkinson, 2007).
The Hanna-Barbera company extensively used this technique in their cartoons. backgrounds would often scroll past the characters and repeat - saving the complexity of animating a longer sequence but the effect could distract audiences and give the production a cheap feel. Despite this, the effect was commonly shown in the Flintstones, where characters could walk past the same piece of furniture 3 times while walking from one room to another.
Cel-Based Process
The production process for a single frame involved several steps (Wikipedia, 2007f):
- Backgrounds would be created for the scene, these were usually painted on an opaque background.
- Any object which was in motion would be redrawn on paper by animators to its new position (or shape, size etc.).
- Character and object outlines would be traced (later photocopied) onto individual cels.
- Colour would be added by painting on the reverse side of the cel - using the outlines to hide irregularities.
- Special effects - e.g. smoke, fire or water would be added.
Following the completion of all of the frames required for a scene, they would be mounted on a peg board individually, and photographed one-by-one onto motion-picture film. When this was played back at normal speed, the illusion of motion was created.
The film could then be edited using traditional cut-splice techniques if necessary. Audio, music, visual effects and titles could then be added in post-production.
Digital Ink and Paint
In the 1990s, the use of computers became common in traditional animation. Animation drawings would be created on a computer using an often studio-specific software program, these would enable the animator to draw the character outlines, fill in colours and export it to the finished product. It dramatically decreased the time taken to create an animation (Wikipedia, 2007f).