Timing and Motion are tied together because in animation the two are basically the same thing. Change the time that it takes a character to complete an action and it will change it's motion.

Timing is interested in how fast an action is happening. This will tell a lot about the mass of an object. If someone lifts up a bowling ball they will do it much slower then they would if they picked up a basketball the two actions could be accomplished using the same motion just different timing. If a character walks sluggishly it would seem like he is walking in water.

Timing can tell about the emotions of a character.

The timing gives some idea as to the forces involved in movement and the mass of an object.

Timing is the precise moment and the amount of time that a character spends on an action. Timing adds emotion and intention to the character's performance. Most three-dimensional computer animation tools allow us to fine tune the timing by shaving off or adding frames with non-linear time editing. Timing can also be controlled and adjusted by placing each character on a separate track, and using sub-tracks for parts of the character such as head, torso, arms and legs.

Expertise in timing comes best with experience and personal experimentation, using the trial and error method in refining technique. The basics are: more drawings between poses slow and smooth the action. Fewer drawings make the action faster and crisper. A variety of slow and fast timing within a scene adds texture and interest to the movement. Most 2D animation is done on twos (2s) each frame is duplicated, so there would be 12 drawings (images) within the 24 frames per second. Twos are used most of the time, and ones (1s) are used during camera moves such as trucks, pans and usually for faster smoother animation. Also, there is timing in the acting of a character to establish mood, emotion, and reaction to another character or to a situation. Studying movement of actors and performers on stage and in films is useful when animating human or animal characters. This frame-by-frame examination of footage will aid you in understanding timing for animation. This is a great way to learn from the others.

Timing, or the speed of an action, is an important principle because it gives meaning to movement- the speed of an action defines how well the idea behind the action will read to an audience. It reflects the weight and size of an object, and can even carry emotional meaning.

Proper timing is critical to making ideas readable. It is important to spend enough time, preparing the audience for, the anticipation of an action; the action itself; and the reaction to the action. If too much time is spent on any of these, the audience's attention will wander. If too little time is spent the movement may be finished before the audience notices it, thus wasting the idea. The faster the movement, the more important it is to make sure the audience can follow what is happening. The action must not be so fast that the audience cannot read it and understand the meaning of it.

More than any other principle, timing defines the weight of an object. Two objects, identical in size and shape, can appear to be two vastly different weights by manipulating timing alone. The heavier an object is, the greater it's mass, and the more force is required to change its motion. A heavy body is slower to accelerate and decelerate than a light one. It takes a large force to get a cannonball moving, but once moving, it tends to keep moving a the same speed and requires some force to stop it. When dealing with heavy objects, one must allow plenty of time and force to start stop or change their movements, in order to make their weight look convincing. Light objects have much less resistance to change of movement and so need much less time to start moving. The flick of a finger is enough to make a balloon accelerate quickly away. When moving, it has little momentum and even the friction of the air quickly slows it up.

Timing can also contribute greatly to the feeling of size or scale of an object or character. A giant has much more weight, more mass and more inertia than a normal man; therefore he moves more slowly. Like the cannonball, he takes more time to get started and, once moving, takes more time to stop. Any changes of movement take place more slowly. Conversely, a tiny character has less inertia than normal, so his movements tend to be quicker. The way an object behaves on the screen, the effect of weight that it gives, depend entirely on the spacing of the poses and not on the poses themselves. No matter how well rendered a cannonball may be, it does not look like a cannonball if it does not behave like one when animated. The same applies to any object or character. The emotional state of a character can also be defined more by its movement than by its appearance, and the varying speed of those movements indicates whether the character is lethargic, excited, nervous or relaxed. Thomas and Johnston describe how changing the timing of an action gives it new meaning.

No inbetweens – The Character has been hit by a tremendous force. His head is nearly snapped off.

One inbetween - The Character has been hit by a brick, rolling pin, and frying pan.

Two inbetweens - The Character has a nervous tic, a muscle spasm and an uncontrollable twitch.

Three inbetweens - The Character is dodging a brick, rolling pin and frying pan.

Four inbetweens - The Character is giving a crisp order, "Get going!" "Move it!"

Five inbetweens - The Character is friendlier, "Over here." "Come on-hurry!"

Six inbetweens - The Character sees a good-looking girl, or the sports car he has always wanted.

Seven inbetweens - The Character tries to get a better look at something.

Eight inbetweens - The Character searches for the peanut butter on the kitchen shelf.

Nine inbetweens - The Character appraises, considering thoughtfully.

Ten inbetweens – The Character stretches a sore muscle.
Limited Animation:
With limited animation as many repeats as possible are used within the 24 frames per second. A hold is also lengthened to reduce the number of drawings. As a rule not more than 6 drawings are produced for one second of animation. Limited drawings are produced for one second of animation. Limited animation requires almost as much skill on the part of the animator as full animation, since he must create an illusion of action with the greatest sense of economy.

Full Animation:
Full animation implies a large number of drawings per second of action. Some action may require that every single frame of the 24 frames within the second is animated in order to achieve an illusion of fluidity on the screen. Neither time nor money is spared on animation. As a rule only TV commercials and feature length animated films can afford this luxury. Animation is expensive and time consuming. It is not economically possible to animate more than is needed and edit the scenes later, as it is in live action films. In 2D animation the director or supervisor carefully plans every action so that the animator works within exact limits and does no more drawings than necessary.