The Link to the 12 principles of Animation videos from YouTube.com
Squash and Stretch
The most important of the 12 principles, the purpose of this is give the a sense of weight and flexibility. For example, a Bouncing ball or more complex structures like the muscles of the body.
Anticipation, is used to prepare the audience for an action, and to make the action appear more realistic. A dancer for example, could be leaping off the floor with the tiptoes edged.
This principle is akin to staging in theatre, as it is known in theatre and film. Its purpose is direct the audience’s attention, and make it clear what is of greatest importance in a scene. Whether that idea is an action, personality, expression or mood.
“the presentation of any idea so that it is completely and unmistakably clear” Johnston and Thomas quoted.
Straight Ahead Action and Pose to Pose
These are two different approaches to the actual drawing process. “Straight ahead action” means drawing out of a scene frame by frame from the beginning to the end of the scene. While pose to pose involves.
Follow Through and Overlapping Action
Follow through and overlapping action is a general heading for two closely related techniques which help to render movement more realistically, and help to give the impression that characters follow the laws of physics, including the principle of inertia.
Slow In and Slow Out
The movement of the human body, and most other objects, needs time to accelerate and slow down. For this reason, animation looks more realistic if it has more drawings near the beginning and end of an action, emphasizing the extreme poses, and fewer in the middle.
Most natural action tends to follow an arched trajectory, and animation should adhere to this principle by following implied “arcs” for greater realism. This technique can be applied to a moving limb by rotating a joint, or a thrown object moving along a parabolic trajectory.The exception is mechanical movement, which typically moves in straight lines.
Adding secondary actions to the main action gives a scene more life, and can help to support the main action. A person walking can simultaneously swing his arms or keep them in his pockets, speak or whistle, or express emotions through facial expressions.
Timing refers to the number of drawings or frames for a given action, which translates to the speed of the action on film. On a purely physical level, correct timing makes objects appear to obey the laws of physics; for instance, an object’s weight determines how it reacts to an impetus, like a push.
Exaggeration is an effect especially useful for animation, as perfect imitation of reality can look static and dull in cartoons. The level of exaggeration depends on whether one seeks realism or a particular style, like a caricature or the style of a specific artist
The principle of solid drawing means taking into account forms in three-dimensional space, or giving them volume and weight. The animator needs to be a skilled artist and has to understand the basics of three-dimensional shapes, anatomy, weight, balance, light and shadow, etc.
Appeal in a cartoon character corresponds to what would be called charisma in an actor. A character who is appealing is not necessarily sympathetic – villains or monsters can also be appealing – the important thing is that the viewer feels the character is real and interesting.