For more details on animating motion, refer to the following TIPS article.
In this lesson, we will introduce how to animate a basic blink.
 The blink
1. Dividing the parts
① We will make the following character below blink. After drawing the character on a single layer, the moving parts, i.e., the eyes and eyebrows, are separated and moved to an animation folder.
② Select the [Select] tool → [Selection pen] sub tool, and make a selection area around the eyes and eyebrows.
If there were no overlaps, we could use other tools such as the [Polyline] sub tool. However, as the edge of the eyebrows are under the bangs, we used the more versatile [Selection pen] sub tool.
③ Once selected, copy and paste the area. An “eye and eyebrow” layer will appear in the [Layer] palette.
④ From the [Animation] menu, select [New animation folder] and create an animation folder (named “b”). We will move the “eye and eyebrow” layer here.
Animation folders created in the [Layer] palette with [Animation] → [New animation folder] will appear in the [Timeline] palette as well.
Note: Cels (frames) cannot be edited unless they are placed on the timeline. Check the timeline when you cannot edit a cel.
⑤ Erase the original eyes and eyebrows with the [Eraser] tool.
⑥ The eyes and eyebrows are now separated from the parts that will not be animated. The folder with the animated parts are named “b”, with anything else named “a”.
2. Drawing closed eyes
① Add 2 layers to folder “b”. There should now be 3 layers in the folder. Each layer will be used as follows.
Layer “1” - Open eye (current eye and eyebrow) cel
Layer “2” - In-between cel
Layer “3” - Closed eye cel
② On the [Timeline] palette, set frame “1”, “2”, and “3” on the frames of animation folder “b”.
③ Enable onion skin with [Animation] menu → [Show animation cels] → [Enable onion skin]. Draw the eye closed on Layer 3 while referencing Layer 1. Try to imagine the motion of the eyelid and pay attention to the width and volume of the closed eye.
Draw near the bottom of the open eye. If it’s too high, the closing motion will look strange.
④ The eyebrows should be nearly identical to Layer 1 other than the edges.
① Draw the inbetween of the open and closed eye on Layer 2. Do this while referencing Layers 1 and 3 by displaying onion skins.
② Connect the edges “1” and “3” of the eyelid with motion arcs. Here, we placed the inbetween on the upper half of the arc to accentuate the motion. This slow-in/slow-out makes the motion more realistic.
A motion arc is a line that indicates the trajectory of a motion. An arc contains dots that specify frames.
In animation, the gradual acceleration of a moving object is called a slow-in. In contrast, the gradual deceleration of an object is called a slow-out. The frames of a slow moving object should near each other, with the opposite being true with a fast object.
③ Carefully draw the inbetween eyelashes while referencing the onion skins and arc. Be careful of overlapping sections.
④ The inbetweened irises should be pulled downward by the eyelids.
4. Checking motion
① Right-click any frame on the [Timeline] palette, and specify cels on the timeline from the pop-up menu. The frames of the motionless Folder “a” should all be 1.
② Here, the timeline of Folder “b”, or the eyes and eyebrows, was set to 1→3→2→1→1.
The first two frames were set to 1(open) → 3(closed) without an inbetween to simulate a blink.
When opening, the frames were set to 3(closed) → 2(inbetween) → 1(open). This makes the opening motion slower than the closing motion.
③ Finish by clicking the [Timeline] palette’s [Play/Stop] and checking the motion.
 The Bouncing Ball
When animating, drawing cels in chronological order is called “Straight ahead action”. This method can be used for simple animation that does not need keyframes. Animating simple shapes with straight ahead action is useful when practicing the movement of objects.
① Draw a ball on the bottom layer. Each ball will be drawn on the following cel.
② Draw the second cel. Displaying the previous cel with [Animation] menu → [Show animation cels] → [Enable onion skin] can make this easier.
We are assuming the ball will bounce as shown below.
③ Continue drawing the following third, forth...etc. frames.
④ The finished animation is a ball that bounces as shown below.
The deceleration at the top of the arc and the acceleration as it falls and bounces is shown using slow-ins/slow-outs. The squash at the bottom is important as well.
Quick animations like this can be made quickly, and will help you get used to the software. Please try it out.