What is Cel Animation?

Hand-Drawn Frames, Layered Techniques, Film History, Animation Pipeline

3 May 2025

This post gives an overview of traditional cel animation—how it works, how it evolved, and where it still shows up today. This isn’t meant to be a comprehensive animation tutorial, but rather a beginner-friendly look at a historically significant and surprisingly technical medium. If you’re curious how animators created motion before computers, or you want to dive into frame-by-frame animation workflows, this will be a good starting point.

Overview

We'll cover the following topics:

  1. What is Cel Animation?
  2. Tools and Materials
  3. Frame-by-Frame Workflow
  4. Modern-Day Relevance

What is Cel Animation?

Cel animation (short for "celluloid animation") is a traditional animation technique where each frame is drawn by hand on transparent sheets called “cels.” These sheets are then photographed in sequence to create the illusion of movement. Cel animation was the dominant form of animation for most of the 20th century and was used to produce classic films from Disney, Studio Ghibli, and Warner Bros.

Each character or object in a scene is typically drawn on separate layers, allowing animators to reuse static backgrounds and animate only the moving parts. This separation of layers is one of the reasons cel animation was both efficient and expressive.

Tools and Materials

Before digital tools, animators relied on a highly tactile workflow. Here’s what a typical cel animation setup looked like:

  • Peg Bar & Paper: To align drawings across frames
  • Pencil & Inking Pens: For sketching and line work
  • Acetate Cels: Transparent sheets to trace finalized drawings
  • Gouache or Acrylic Paint: For coloring the back of each cel
  • Animation Camera Stand: To capture each frame onto film
  • Exposure Sheet (X-Sheet): A timing chart used to plan out frame sequences and dialogue sync

Frame-by-Frame Workflow

Cel animation is labor-intensive and often broken down into a pipeline of roles:

  1. Storyboard: Plan out key moments and framing
  2. Layout: Design backgrounds and character positioning
  3. Key Animation: Draw the essential poses of a movement
  4. Inbetweening: Fill in the frames between key poses
  5. Cleanup: Refine rough sketches into clean outlines
  6. Cel Painting: Trace and paint characters onto acetate
  7. Photography: Shoot each cel over the background frame by frame

At 24 frames per second (fps), even a 10-second shot could require hundreds of hand-painted cels. Timing, consistency, and patience are critical to make the motion feel fluid and believable.

Modern-Day Relevance

Although cel animation has largely been replaced by digital techniques, its influence is still everywhere. Shows like The Simpsons began as cel animations. Films like The Lion King (1994) and Akira (1988) are revered for their cel artistry. Even modern 2D animation tools like Toon Boom Harmony simulate the cel animation workflow digitally.

For hobbyists and indie creators, cel-style animation offers creative freedom and a unique look that digital tools struggle to replicate. There’s also a growing trend of animators returning to analog workflows for stylistic and nostalgic reasons.

Final Thoughts

Cel animation is more than a nostalgic process—it’s a precise craft that bridges drawing, photography, and storytelling. Learning the foundations of cel animation, even as a digital artist, can deepen your understanding of movement, timing, and visual storytelling. If you're exploring animation from a technical or artistic angle, try sketching a few frames yourself or photographing a flipbook—it’s a humbling and rewarding exercise.