In-Betweening

Definition

In-betweening is the manual or assisted creation of transitional frames that bridge keyframes, establishing continuous motion in hand-drawn animation. In traditional workflows, in-betweeners—usually junior artists—follow timing charts and model sheets to ensure consistency with the lead animator’s vision.

Historical Roots

During the Golden Age of Disney, large studios employed “in-betweeners” in assembly-line fashion: lead animators sketched primary poses; assistants filled the intervening frames. This division of labor enabled prolific output on features like Snow White (1937) and Sleeping Beauty (1959).

Workflow & Techniques

1. Keys & Extremes: Lead animator draws principal frames and major breakdown poses.
2. Timing Charts: Define the number of in-betweens between each key, controlling speed and rhythm.
3. Clean-up: In-betweeners refine pencil sketches into final lines, preserving style and proportions.
4. Digital Assistance: Modern software can auto-generate rough in-betweens, which artists then polish.

Contemporary Applications

While CGI dominates many productions, in-betweening persists in 2D animation studios worldwide. Software like Clip Studio Paint and OpenToonz integrates digital onion-skinning and auto-tweening to streamline hand-drawn workflows.

Trivia

• Some veteran in-betweeners are prized for their knack in preserving character charm across hundreds of frames.
• The term “in-betweening” inspired the shorthand “tweening” when digital interpolation tools emerged.