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Cel animation separates moving elements from a background, paints them on transparent sheets and photographs the combinations frame by frame. A physical cel is an intermediate production material. An image with a traditional animated look may have been made without one.
Design, storyboards, key drawings and in-betweens establish a shot and its movement. Key drawings set important poses; in-betweens connect and organize them. These paper drawings are a different production material from the painted transparent sheets later photographed with the background.
Tracing transfers the finished paper drawing to a cel, by hand or with transfer equipment. Unpainted transparent areas allow the background to show through. Lines establish outlines and some colour boundaries; sheet, linework and paint are distinct components. Registration also matters: a familiar three-peg bar holds matching holes in paper and cels to keep tracing and painting aligned. The holes belong to the working material rather than the pictured character.
Colour is applied to the reverse using animation paint and colour specifications. Viewed from the front, the outlines remain in front of the filled areas. A large team follows shared colours and shadow divisions, rather than inventing a new palette for each sheet.
Moving figures are painted on cels, while a background is commonly painted on paper. Replacing selected cels lets the background remain across successive images. Separate moving elements may occupy several layers, with the arrangement determined by the shot.
This generic teaching example is not a shot from a film. Background B keeps the same sky and ground. Cel A1 places the blue ball on the left; replacing it with A2 places the ball on the right. Unpainted transparent areas continue to reveal B. Showing these with intermediate positions in sequence would organize the displacement into movement. The two still diagrams identify what is held and what changes.
The camera records the background and cel combination onto film. Showing the recorded frames in sequence produces motion. Each projected frame need not require a newly painted cel: a drawing can be held for several frames or an action reused. The number of drawings depends on movement and production choices.
Camera operators do not simply change sheets by intuition. A 1977 television-technology account connects the shot’s drawing count, timing and camera instructions to an exposure sheet specifying which cel to use and for how many frames.
For a teaching example at 24 screen frames per second, hold A1 for frames 1–2, A2 for 3–4 and A3 for 5–6. Extending that two-frame pattern through the second gives 24 screen frames from 12 different drawings. Holds still depend on the movement and shot; this is an example rather than a universal quota. The photographed paper sheet is genuine production material, while the simple table explains this example’s numbering.
| Screen frames | Background | Moving cel |
|---|---|---|
| 1–2 | B | A1 |
| 3–4 | B | A2 |
| 5–6 | B | A3 |
Cel is short for celluloid, but later production adopted cellulose acetate and other materials. A collectible casually called a celluloid is not necessarily made of cellulose nitrate. Documentation and material analysis establish the composition and condition of a particular object.
Transparent-sheet layering developed in the United States in the 1910s, with Earl Hurd’s patent application of 19 December 1914, granted on 15 June 1915, an important milestone. Early Japanese animation also used paper drawings and cutouts, so it cannot all be labelled cel animation. Cel production developed in Japan around 1930.
Shigeji Ogino’s 1937 documentary Shikisai manga no dekiru made records Noburō Ōfuji making colour-cel animation for Katsura-hime. Kawasaki City Museum uses the film to explain early production. The motion-picture film recording the scene and the painted transparent sheets shown in it are different materials.
Toei acquired Nichidō Eiga in 1956 and renamed it Toei Dōga. It completed Hakujaden in 1958 and began the television series Wolf Boy Ken in 1963. Drawing, tracing, painting, backgrounds and photography had to work together in sustained production. Hiroshima MOCA’s 2000 exhibition used storyboards, key drawings and cels as distinct evidence of this system.
Toei dates computer-image research to 1980, completion of CATAS software to 1991 and the start of RETAS-based television digitization to 1997. Digital painting and compositing increasingly replaced physical cels and film photography. A University of Tokyo dissertation records physical-cel production on Sazae-san continuing until 2013. This provides a specific example of physical-cel work continuing relatively late.
Two dated production accounts locate the change. The 1977 description transfers lines to sheets, paints their reverse, checks them against backgrounds and exposes the combinations onto film according to the sheet. A 2020 report on Zero-G’s Science Fell in Love, So I Tried to Prove It describes drawings digitized and brought into a computer for colouring and compositing instead.
The report still calls compositing “photography,” although data are now combined on a computer. Exposure instructions continue to connect drawing numbers, holds and shot duration. Tools replace physical cels and the camera stand, while relationships between backgrounds and moving elements, drawings and time remain.
Production materials became objects of collecting, exhibition and research. A study published by the Japan Society for Animation Studies analyzed two cels from Hideo Watabe’s collection, addressing damage and preservation. Suginami Animation Museum also offered reverse-painting instruction in 2026. Teaching exercises, reproductions and original camera-used production cels require different identifications.
Drawings made on paper can be scanned, coloured and composited digitally without producing individual physical cels. That remains distinct from 3D cel shading, which uses rendering choices to suggest flat colours and outlines. Material, method of drawing movement and visual style are separate questions.
Unpainted areas allow the lower background to show through.
The reverse, preserving the front linework.
No. They are different production materials.
No. It can colour hand-drawn movement.
No. Purpose and provenance must be distinguished.
Background B is held while the cel carrying the ball at another position is replaced.
Twelve; screen-frame count differs from the number of new drawings.
Digital colour and compositing replace painted sheets and camera exposure, while drawings, backgrounds and timing still need coordination.