One very important thing, something I know I have to get better at, is timing. Everything has to be timed right for the animation to look natural. We might not think about it but it takes time and several frames to take a step, if the character is walking slowly it takes more time and equally more frames to take one step then if the character was walking fast.
Anticipation is there to tell the audience what is going to happen. Like in this example:
You can see that before the man can do the action of sending a freesbe he leans back, this is the anticipation. Anticipation is the time before an action that gives the character time to think of what to do next and it tells the audience what is about to happen.
One of the first things we learned to animate was a bouncing ball. What makes a ball look soft is that it changes shape when it bounces. See this example:
When a ball hits the ground it flattens out, it is squashed on the ground. The more power is used to hit the ball in the ground the more it gets squashed and the higher it bounces of the ground again. If the ball is stretched when it is flying through the air, like at the top of the example, it makes it look like it is going really fast.
That can also be called exaggeration. Exaggeration is often used in cartoons to squash and stretch characters.
See the superhero is flying really fast through the air so he is stretched out, but then he hits the wall and gets squashed. In the end it all tells us that the superhero was flying really, really fast. Below I also drew a example of a man jumping with a lot of exaggeration, when he jumps up he is stretched and when he lands he is squashed.
Another example of exaggeration is face expressions:
By exaggerating the face expressions of characters you make it a lot clearer to the audience what their reactions and feelings are.
Arcs are what the name says arcs. Let me give you an example:
As you can see arcs are the animated movement of things that move in arcs, like in the picture the movement of the arm and the travelling of the ball are both arcs.
Follow through and overlapping are used when not everything in the frames is moving at the same speed. Like here:
Here is a guy in a cape, he moves his arm but the cape doesn't follow straight away, it follows the arm but takes longer before it holds still in the new position.
Secondary action is when one action triggers another action. Like if we animate a car driving through the frame, one action is the car itself moving across the screen and another is the wheels turning.
Another principal that is important is slow in and slow out. If the car from above was parked when the animation started, we would have to animate it to slowly gain speed until it had the speed we needed other wise it wouldn't look natural, the same goes if the the car was to stop at the end of the animation we would have to slow it down first. This is called slow in and slow out.
I made an example with an UFO:
The UFO starts at the left gains speed and then slows down and stops at the right. As you can see it is closer between UFOs on the sides than in the middle. This is because the less difference there is between frames the slower the movement seems.
It might be clearer here. The dot starts at the lower left corner and stops at the upper right corner.
Staging is to set the mood of the animation right. If it is a depressing story use dull colours and have it rain and things like that and if it is a happy story use bright colours and bird song and things like that.
The characters in an animation must have appeal. No matter if it is the hero or the villain, they must have the appeal to make the audience keep watching the animation till the end.
And finally straight ahead action and pose-to-pose action are two different ways to animate. In straight ahead animation you draw frame by frame in the right order, this can make it hard to control the size of the animated character or object, it might slowly get smaller or bigger without you noticing. But then we have pose-to-pose animation, where all the key frames are drawn first and then all the betweens are drawn afterwards, this makes it easier to control the size of the character or object you are animating.
