How animators save money-
Limited animation
In an animated scene the characters may not be moving but just talking. The head and body may not move, just the mouth. This means that the mouth is the only part that has to be redrawn in those frames. This is known as limited animation. The process is used in most television animation where 3 dimensional and lifelike appearance is not a concern. This saves lots of money and animation time.
Shooting on twos
Moving characters are often shot "on twos". This means that one drawing is shown for every two frames of film (which usually runs at 24 frames per second). Instead of 24 frames drawn for each second, only 12 are required.
If a subject is supposed to perform a quick movement, it may be needed to revert to animating "on ones", because 12 frames per second may not convey the movement properly.
Television animation may be filmed on only six or eight drawings per second.
Animation loops
A loop is just reusing a sequence of frames that show movement. This is used for walking, running or any action that may be repeated. You can spot these when the same background goes by the character more than once.
In the case of walking, the character is animated taking a step with his right foot, then a step with his left foot. The loop is created so that, when the sequence repeats, the motion is seamless. A cartoon character walking on a street may appear to keep passing the same scenery over and over.
multiplane effect, or the parallax process is a way to add depth to 2D scenes.
Artwork is placed on different layers of glass or clear plastic. As a camera moves along the artwork it makes the artwork look almost 3 dimensional. This would be similar to driving down a street with trees and houses. The trees move as you drive along. This could be done by moving the camera vertically or horizontally.
Sometimes artwork is cut to shape and fastened to a rotating platform. The platform can then be rotated while the camera remains fixed. This gives the effect of 3d movement. This rotation is known as rotoscaping.
Some 3d cad programs can duplicate these effects and create amazing effects similar to the above effects.
Sometimes 2d and 3d animation is combined for special effects. This enables 3d animation to have a more traditional animation look.
Photocopying
An original drawing can be photocopied on paper or clear plastic and then modified to show motions like walking or talking. This can be done in bw or full color provided the same machine is used for the successive layers or cels. This saves complete hand redrawing and coloring for each new cell. Enlarging or reducing allows the simple creation of perspective views.
