For nearly a century, hand-drawn cartoons defined our childhoods and shaped the global entertainment industry. From the fluid motion of early Disney classics to the dynamic action of Japanese anime, these visual stories share a common technical foundation. This technique is known as cell animation, and despite the rise of computer-generated imagery (CGI), it remains a vital and respected art form.
Understanding how this traditional method works provides valuable insight into the history of film. It also highlights the incredible level of skill required to bring static drawings to life. Whether you are an aspiring animator or simply a film enthusiast, appreciating the mechanics of this medium changes how you view your favourite animated features.
What is Cell Animation?
Cell animation, often spelled “cel animation,” derives its name from celluloid, the transparent material originally used in the process. Before this innovation, animators had to draw the entire image—background and characters—for every single frame. This was an incredibly labour-intensive task that limited the length and complexity of early animated films.
The process changed in 1914 when Earl Hurd patented the use of clear sheets. This breakthrough allowed artists to draw moving characters on transparent layers while keeping the background static. This separation of elements drastically reduced the workload, as background artists only had to paint a scene once, while character animators focused solely on movement. This efficiency kickstarted the golden age of animation and became the industry standard for decades.
The Cell Animation Process
The creation of a hand-drawn animated film is a complex undertaking that involves multiple stages of production. It begins with a storyboard, which acts as a visual script, mapping out the action and dialogue. Once the timing is established, senior animators draw the keyframes. These are the primary drawings that define the start and end points of any movement, effectively establishing the acting and emotional performance of the character.
Following the keyframes, assistant animators or “in-betweeners” draw the frames that go between the main poses. This step creates the illusion of fluid movement. In the traditional workflow, these pencil drawings are then transferred onto clear acetate sheets using ink. This was originally done by hand, though later years saw the introduction of xerography to photocopy the pencil lines directly onto the cel.
Once the lines are transferred, the cells are sent to the ink and paint department. Artists flip the acetate over and paint the colours on the reverse side. Painting on the back creates a flat, solid fill while preserving the crispness of the inked lines on the front. Finally, the finished cells are placed over the painted background and photographed one frame at a time using a rostrum camera. When played back at 24 frames per second, the separate drawings merge into a seamless performance.
Tools and Technologies
The tools required for this art form have shifted significantly over time. In the 20th century, the animator’s toolkit consisted of light tables, peg bars to keep paper aligned, pencils, acetate sheets, and specific acrylic paints designed to stick to plastic. The physical nature of the medium meant that mistakes were costly and difficult to correct once the paint had dried.
Today, while the aesthetic of traditional animation persists, the tools have largely gone digital. Software such as Toon Boom Harmony, TVPaint, and Adobe Animate allows artists to draw directly onto screens. These programs simulate the look of ink and paint on acetate but offer layers, undo functions, and instant playback. This digital evolution maintains the hand-drawn charm while removing the physical waste and chemical processes associated with traditional celluloid and photography.
The Value of Hand-Drawn Art
Cell animation represents a pivotal chapter in visual storytelling. It is a discipline that demands patience and precision, rewarding the creator with visuals that possess a distinct human touch. While the technology has moved from physical plastic sheets to digital tablets, the core principles of squash, stretch, and timing remain unchanged. Understanding this history allows us to better appreciate the artistry behind the moving images we see on screen.