|PRINCIPLES OF ANIMATION
The actual point I want to make here is not how much or how little you should exaggerate the timing, but rather, whether or not it reads properly for the audience.
The number one question I am asked by people (other than, "What does the Claw look like?" is, "How long does it take to animate______________?" (fill in the blank along with an arm and hand action of some sort.)
The joke answer is, "One million drawings." The real answer is, I don't know, it all depends on how long you think it should take, and what looks right.
I try to get my students to time their animation at the key pose stage when they start animating the Broad Jump assignments and start to get really adamant about it on the Step Up/Step Down assignment. Invariably, I will have students show me pencil tests of their keys all shot on twos (each drawing exposed for two frames). In most cases, this is inappropriate timing. For the Broad Jump assignment, a key could be the push off point just before the jump up and the next key is the high point. If these two drawings are shot on twos, that means the action from low point to high point takes 4 frames or 1/6th of a second, which is impossibly fast. If you look at the ball bounce assignment, we had 4 inbetweens to ease into the high point. Shot on twos that would be 12 frames total (including the two keys) or 1/2 a second, which is far more reasonable. To properly time the jump keys, this would mean exposing the first key pose at the low point for 10 frames (2 for the key and 8 for the missing 4 inbetweens) and then 10 frames for the high point key (2 for the key and 8 for the missing 4 inbetweens into the low point key).
The resulting pencil test will be jerky, but the timing will be accurate. Many students have used this excuse when they show me keys shot on twos, "Well it's smoother this way."
I respond with, "So, why didn't you shoot it all on ones?"
"It would be way to fast on ones!" they say back to me.
"But it's way too fast on twos right?"
Not properly timing your keys could be for either or both of the following reasons:
(I sat and tried to think of any other reason and couldn't come up with any.)
Either one of these is unacceptable.
If you don't know the timing or haven't thought about it, you need to figure it out.
Act it out.
Does the entire length of your pencil test match up to the overall timing you just figured out? Most likely, it doesn't. Your pencil test is way shorter.
Now go back and time it out again, this time focussing on the individual actions.
Let's use the broad jump as an example:
How long does it take you to swing your arms back and forth? Put your hands at your sides and relax. Now swing your arms forward and then to the back and then forward again.
I timed it out to 2 seconds. That's 48 frames or 24 drawings.
The action I described would have 4 keys poses:
24 drawings ÷ 3 (that's the space between each key) = 8 drawings from one key to the next (including the first key pose, but that's a simple mathematical subdivision based on equal parts. (Notice that it works out to 25 drawings total.)
Here's what they would look like with the slo in and slo outs:
This modifies it back down to 24 drawings, but still, the basic timing is there.
Shoot the keys and time it then play it back to see if it works. If it doesn't, make adjustments to make it longer or shorter. Yes, it will be jerky, but you need to see how long it takes.
Back to a student example from the Step Up/Step Down assignment. At the top of the stairs their character pulls out a bottle and takes a drink. The student timed the drinking action with three drawings all shot on twos which lasted 6 frames on screen or 1/4 of a second, not nearly enough time to take a drink.
The student was ticked off at me when I suggested that it wasn't enough time to take a drink.
"He's just finishing off the last of it." he said.
The character then anticipated back with one drawing and then threw the bottle away with an extreme stretched out arm, again, timed for two frames each. Total time elapsed from drinking pose to throwing was 10 frames, less than 1/2 a second.
"He's angry because it's all gone." he explained. "That's why he threw it so fast."
To act this action out with a thought process of the character thinking to himself, Glug, glug, glug... reaction to it being empty... "Aw man, that's the last of this stuff... Crap!... I wanted more!" anticipate back and then throw.
This timing can vary quite a bit from the bare minimum 7 seconds to a much more emotional 12 seconds.
Try it yourself and see what it works out to.
The more drunk the guy is, the longer it will take.
As with anything... It All Depends.
The bottom line here is: don't default to timing your drawings on twos, it rarely works unless maybe you've done some straight ahead animation and even then you probably need at least one inbetween for every two drawings.