Onion-Skinning

Definition

Onion-skinning is the practice of displaying multiple frames—past and future—semi-transparently on top of the current drawing. This visual reference helps animators maintain consistent motion, proportions and timing when drawing frame-by-frame animations.

Evolution & Tools

In traditional workflows, animators used thin paper to trace over previous drawings, aligning key shapes to achieve smooth transitions. Digital animation software—such as TVPaint, Toon Boom Harmony and Adobe Animate—automates onion-skinning, allowing users to adjust the number of frames visible, opacity levels and color tints for ease of reference.

Benefits & Best Practices

• Timely Feedback: Immediate visual cues on spacing and arcs.
• Consistency: Ensures characters maintain volume and alignment.
• Efficiency: Reduces redraws and corrections by anticipating motion paths.

Animators often toggle onion-skinning on and off when refining in-betweens or cleaning up line work to avoid visual clutter.

Trivia

• The term derives from layers of translucent onion skin paper used in early animation desks.
• Some software offers “peelback” geometry views for 3D rigs, a digital cousin to onion-skinning.