The Hand-Drawn Animation Process

Before the advent of digital imagery, hand-drawn cel animation represented one of the most labour-intensive and structurally complex art forms in commercial cinema. The creation of a traditional animated feature began long before any visual artist put pencil to paper, starting instead with a written concept or treatment. Once the broad narrative concept was approved by studio executives, scriptwriters drafted a full screenplay detailing dialogue, physical actions, and crucial scene transitions. From this literary foundation, storyboard artists translated the written text into visual sequences, drafting hundreds of sequential sketches that mapped out camera angles, staging, and basic compositions. These storyboards functioned essentially as an oversized visual comic strip of the entire project, allowing directors to identify narrative flaws, pacing issues, and compositional weaknesses at a relatively inexpensive stage of development.

To assess narrative timing and rhythm more accurately, the individual storyboard panels were filmed in sequence and paired with a temporary soundtrack to create what the industry called an animatic. This preliminary reel included rough musical cues, basic sound effects, and an early audio recording known as a scratch track. By viewing the animatic, production teams could fine-tune the exact duration of each scene before committing costly artistic resources to full-scale animation. Once the timing was firmly locked, professional voice actors recorded the final dialogue tracks in sound studios. Sound technicians subsequently analysed these audio recordings frame by frame, noting phonetic sounds and their precise durations onto specialised production grids called exposure sheets. These charts formed the comprehensive master blueprint that guided every subsequent visual department.

With the exposure sheets completed, the project moved to the character animators. Senior artists, often designated as key animators, did not draw every single frame of a sequence. Instead, they focused exclusively on extreme poses and critical moments of dramatic action, known as keyframes, which defined the physical trajectory and emotional weight of a movement. Along the margins of their paper, key animators drew a timing chart—a coded diagram indicating to assistants how many intervening drawings were required between poses and how the motion should accelerate or decelerate. Assistant animators then contributed breakdown drawings, which established the intermediate paths of movement connecting these major extremes and ensured that the volume of the character remained consistent.

Once the key poses and breakdowns were established, the scenes were passed down to junior artists known as inbetweeners. Their task was to complete the remaining intermediate sketches, ensuring smooth transitions across all twenty-four frames per second of projected film. To verify that the motion flowed naturally and that characters did not appear distorted, the loose graphite sketches were captured using a basic video or photographic camera in a process termed a pencil test. If the resulting sequence appeared jerky or inconsistent, artists could quickly erase and modify the graphite drawings before the sequence proceeded to the significantly more permanent and expensive stages of the pipeline.

Approved graphite drawings were next sent to the clean-up department, where specialised artists traced over the rough lines onto fresh sheets of paper to create precise, uniform contours. Following this refinement, the images entered the ink-and-paint phase. In the early decades of the craft, inkers manually transferred the clean lines onto transparent sheets of cellulose acetate known as cels, using dip pens and black ink, though later studios frequently adopted electrostatic transfer methods. Once the outlines were dry, painters applied specialised opaque paints—typically vinyl or acrylic emulsions—to the reverse side of the cel. Painting on the back prevented the wet pigment from obscuring the crisp inked lines on the front and eliminated visible brushstrokes when viewed from above.

Simultaneously, background artists produced the static environments against which the animated characters would perform. Unlike the transient character cels, which changed with every frame or two, a single background painting might remain on screen for several seconds. These elaborate settings were typically rendered in opaque gouache, watercolour, or oil paints on heavyweight illustration board. Great care was taken to maintain colour harmony and lighting consistency between the backgrounds and the painted cels, ensuring that the moving characters stood out distinctly without seeming visually disconnected from their physical surroundings.

The culmination of the traditional workflow took place in the camera department. Each painted cel was carefully dusted to remove lint, placed precisely over the corresponding background painting using registration pegs, and held completely flat beneath a heavy glass plate on a rostrum camera setup. For complex scenes requiring a sense of three-dimensional depth, studios utilised a multiplane camera, which suspended several layers of artwork on separate horizontal glass tiers at varying distances below the lens. As the camera panned or moved closer, these layers shifted at different speeds, creating an illusion of physical parallax. Each unique configuration of layers was photographed frame by frame onto motion picture film, ready for final chemical processing, optical compositing, and theatrical distribution.