Timing is everything.
Remy doesn’t just eat food – he savors it. It’s part of his character. Above, he takes one bite of a strawberry. In a hurry, someone may take one or two seconds. Here, Remy takes 6.3 seconds. We know definitely he loves food, and the Timing of the shot says so.
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 abide to the laws of physics; for instance, an object’s weight decides how it reacts to an impetus, like a push. Timing is critical for establishing a character’s mood, emotion, and reaction. It can also be a device to communicate aspects of a character’s personality.
You can have the perfect amount of squash and stretch, the most beautiful staging and the curviest arcs – but if your timing is off, it can make everything fall flat.
Timing is the glue that holds all the elements of animation together and sells the whole package.
Physical timing is exactly what it sounds like: how objects should behave in the physical world due to gravity, weight, and mass. This isn’t to say that your actions must be pinpoint accurate, but they should at least be contextually believable and not jarring. You could say that physical timing relates to action that the viewer expects to happen, subconsciously or otherwise.
Theatrical timing relates to acting and performance: how long an action takes, or how long you hold a pose. For example, a character walking slowly might be doing so because they’re old, injured, unhappy or just plain huge… Changes in spacing can make drastic differences to the mood or interpretation of the performance by the viewer.
Timing gives meaning to movement. Small changes in the spacing or your keys can make a world of difference to the understanding and impact of your scene – even without modifying a single pose. Observation of movement around you and even analyzing filmed footage frame by frame is essential to developing your understanding and interpretation of Timing.
From Frank Thomas and Ollie Johnson:
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 film footage will aid you in understanding timing for animation. This is a great way to learn from the others.