Onionskinning

Onionskinning is a technique used in animation, digital art, and video editing to facilitate frame-by-frame analysis and creation. The term originates from the traditional animation process, where multiple transparent sheets, or "cels," were layered to visualize motion and consistency between frames. The outermost layer displayed the current drawing, while underlying layers showed the previous frames, allowing artists to make precise adjustments and maintain smooth motion.

In digital applications, onionskinning is implemented as a visual overlay feature that displays semi-transparent copies of preceding and/or subsequent frames. This enables artists and editors to see the relationship between frames without removing the current drawing or image, aiding in accurate timing, motion continuity, and editing decisions. The transparency level and the number of frames visible can typically be adjusted, providing flexibility based on artistic needs.

Onionskinning is especially valuable in animation production, where it helps animators create fluid motion by comparing consecutive frames and ensuring consistent proportions and movement. In digital illustration, it assists in maintaining spatial accuracy across complex sequences. In video editing, the technique can be used to compare frames during cuts or transitions to ensure seamless flow.

While the concept has evolved with technology, the core purpose remains the same: to provide visual reference that improves precision and coherence during the iterative process of creating or editing motion and images. Overall, onionskinning is a foundational technique that enhances the fidelity and efficiency of animation, digital art, and editing workflows.

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