In traditional animation, a lead animator draws the key poses: the ball at the top of its arc, the ball squashed on the floor. Someone else then draws everything in between. For decades that someone was called an in-betweener.
It was where most animators started. Careful, repetitive work, on a light table, late at night, and nobody outside the studio ever knew your name. We named the studio after it on purpose. The key poses tell you what happens. The in-betweens tell you how it feels.
Keys say what, in-betweens say how
Take a ball moving from left to right. Two key poses, start and end, are enough to describe the action. But the frames you put between them decide whether it is a heavy bowling ball, a balloon, or a ball being shoved by someone in a hurry.
Space those in-betweens evenly and the ball moves at a constant speed. It looks mechanical, like a parcel on a conveyor belt. Bunch them up near the keys and spread them out in the middle, and the ball eases out of rest, travels and eases into its stop. Same two keys, same nine frames, a completely different sense of weight.
Frame counts matter too. We animate most character work at 24 frames per second, on twos, which means each drawing holds for two frames. That gives a slightly crisp, hand-made rhythm. Fast actions switch to ones, a new drawing every frame, so a quick turn of the head never strobes.
LinearEven gaps
EasedSlow out, slow in
Two balls travel between the same two key poses with nine frames each. The linear ball has evenly spaced in-between frames and moves at a constant speed. The eased ball has frames bunched near both keys, so it starts and stops gently.
Easing is spacing, written as a curve
Animators call this slow in and slow out, one of the twelve principles Disney's animators wrote down decades ago. In software it shows up as an easing curve: time along the bottom, distance up the side. A straight line is linear motion. An S-shaped curve is the ease you just watched.
Most motion that feels cheap online is linear by default, because linear is what you get when nobody decides. Most motion that feels expensive was eased by hand, and not with a preset. We tune curves per object, using a few rules of thumb:
- Heavy things start slowly and stop late. A logo slab or a rendered product gets a long ease out and a firm landing.
- Light things react fast. Icons, cursors and small type get short, snappy curves with a tiny overshoot.
- Interfaces move like interfaces. Screens in an explainer borrow the curves your real product uses, so the video feels honest.
- Nothing moves at constant speed unless it is a machine, and even then we add a little drift.
Nobody remembers an in-between. They only remember whether the motion felt right.
Where the feeling hides
Spacing is the start. The rest of the feeling lives in a few small habits that all happen between the keys. Overlap: a character stops, but their scarf keeps going for four more frames. Anticipation: a tiny dip before a jump, so the eye knows where to look. Arcs: almost nothing alive moves in a straight line, so our in-betweens travel along curves even when the keys sit level. Squash and stretch is the fourth: a ball flattens a little on impact and stretches as it speeds up, so it keeps its volume while showing its speed.
On Pulse, the music video at the top of this note, the characters hit their key poses on the beat. Everything that makes them feel like they are dancing, rather than snapping from pose to pose, happens on the frames in between, timed to the swing of the track rather than the click.
Why this matters for a product video
You might think this is only for characters. It is not. The same rules decide whether a dashboard sliding onto screen feels trustworthy or twitchy, whether a price counting up feels confident, and whether a logo reveal feels earned or stamped on.
Here is the arithmetic. A sixty second explainer is around 1,440 frames. Our animators might set 150 of them as keys. The other 1,290 are in-betweens, and each one is a small decision about weight, timing and intent. Software helps generate them, but every curve it follows is one we set by hand and check frame by frame before you see a draft.
When a client tells us a video feels premium but cannot say why, this is usually what they are noticing. Not the illustration style, not the colour, but thousands of in-between frames that someone cared about. That is the job we named ourselves after, and it is still the part of the work we love most.
