Cel animation built films one hand-drawn frame at a time
Before computers dominated studios, classical animation meant drawing every frame by hand, then transferring art to transparent cels painted on the reverse and photographed over backgrounds. Dialogue was often recorded first so mouths and motion could lock to sound—except in many early and Japanese productions that post-synched.
Traditional animation—also called classical, cel, or hand-drawn animation—was the leading American feature method through much of the twentieth century until computer pipelines took over. Each frame begins as a drawing. Today the craft often survives as digital ink-and-paint: hand-drawn work composited digitally. Production typically moves from script to storyboard panels that map staging, acting, and camera moves, with boards reworked until directors approve the flow.
Voice tracks usually precede full animation so performances sync; scratch tracks carry dialogue and temp music while final score and effects arrive in post. Japanese animation and most pre-1930 sound cartoons often recorded sound afterward by watching finished picture—Fleischer kept post-synching through much of the 1930s, leaving muttered ad-libs in Popeye and Betty Boop shorts. Designers issue model sheets and turnarounds; maquettes may show characters in three dimensions. Timing directors fill exposure sheets frame by frame, or bar sheets when music leads.
Key animators draw major poses on peg-registered paper, then pencil-test scenes; assistants and inbetweeners fill missing frames before clean-up. Approved drawings transfer to cellulose acetate cels—outlines inked or photocopied, colour painted on the reverse—stacked over painted backgrounds and shot under a rostrum camera. Registration holes stop jitter. Disney's wartime ink-and-paint disruption later encouraged Ub Iwerks's xerography. Dope sheets tell camera operators whether drawings hold for one, two, or three frames.
Source: Traditional animation
