in-betweening

In the classic 2D animation process, you work in a strict hierarchy: the lead animator sets the extreme positions — the so-called keyframes. In between lies the entire visual space that the in-between artist must fill. This is not simple copying between two drawings. You interpolate movement, weight, easing — everything that lies between action and reaction. At 24 frames per second, a single cut of three seconds of material can mean 72 individual drawings. Only three to five of these are keyframes. The rest? Your work.

The quality of the in-between material determines the fluidity of the animation. Too few frames between the keys appear jerky, too many waste time and budget. With experience, you recognize patterns: a fast arm movement requires a different in-between density than a slow gaze pan. The lead shows you through their keys whether they are thinking straight-ahead or pose-to-pose — this defines your approach. Tight keys allow for more precise interpolation. Loose keys require interpretive drawing.

Digitally, the mechanics change, not the logic. Motion capture or 3D software often generate in-betweens automatically — but an AI tool and an experienced animator produce completely different movement qualities. Even in the 3D context, you critically review the generated in-between frames: Does the curve look natural? Does the movement follow the actor's timing? This is where the difference between mechanical interpolation and motion design becomes apparent.

On set — yes, even there — you see in-between logic in motion blur and in the smearing of fast cuts. In the traditional drawn-frame process, in-between work is the entry-level job for many animators. Those who work carefully here, who don't just connect the keys but orchestrate them, become leads. Those who overlook this remain stuck in the craft. Mastery lies not in the striking poses — the lead handles those. It lies in the invisible moments in between.