Editing Inbetweening (section)

== Frame frequency ==
[[File: Fantasmagorie (Cohl).GIF|thumb|Animation "on twos" has been used for over 100 years, being used for instance in ''[[Fantasmagorie (1908 film)|Fantasmagorie]]'' (1908).]]
Typically, the key [[animator]] does not make drawings for all 24 frames required for one second of film length. In large studios, a specialized inbetweener artist fills in the gaps between the key drawings. Only very fast movements require 24 drawings per second, which is referred to as animating "on ones". Most movements can be done with 12 drawings per second—called animating "on twos", drawing one out of every two frames. When the number of in-betweens is too few, such as four drawings per second, an animation may begin to lose the [[illusion]] of the movement altogether. Computer-generated animation is usually animated "on ones." Frame frequency often varies depending on animation style and is an artistic choice. Animation "on twos" has been used for over 100 years; ''[[Fantasmagorie (1908 film)|Fantasmagorie]]'' (1908), widely considered the first fully animated movie, was animated on twos.

Modern animation uses various techniques to adapt frame rates. Slow movements may be animated on threes or fours. Different components of a shot might be animated at different frame rates{{emdash}}for example, a character in a panning shot might be animated "on twos", while everything in the shot is shifted every frame ("on ones") to accomplish a panning effect. Optical effects such as motion blur may be used to simulate the appearance of a higher frame rate.