Computer Animation Production System in the context of Traditional animation

A cel, short for celluloid, is a transparent sheet on which objects are drawn or painted for traditional, hand-drawn animation. Actual celluloid (consisting of cellulose nitrate and camphor) was used during the first half of the 20th century. Since it was flammable and dimensionally unstable, celluloid was largely replaced by cellulose acetate (cellulose diacetate and cellulose triacetate) and polyester. With the advent of computer-assisted animation production (also known as digital ink and paint), the use of cels has been all but obsolete in major productions. Walt Disney Animation Studios stopped using cels in 1990, when Computer Animation Production System (CAPS) replaced this element in their animation process. In the next decade and a half, other animation studios phased cels out as well in favor of digital ink and paint.

The Rescuers Down Under is a 1990 American animated adventure film produced by Walt Disney Feature Animation and released by Walt Disney Pictures. It is the sequel to the 1977 film The Rescuers. In this film, Bernard and Bianca travel to the Australian Outback to save a young boy named Cody from a villainous poacher who wants to capture an endangered golden eagle for money. Directed by Hendel Butoy and Mike Gabriel from a screenplay by Jim Cox, Karey Kirkpatrick, Byron Simpson, and Joe Ranft, the film features the voices of Bob Newhart, Eva Gabor (in her final film role), John Candy, and George C. Scott.

By the mid-1980s, The Rescuers had become one of Disney's most successful animated releases. Under the new management of Michael Eisner and Jeffrey Katzenberg, a feature-length sequel was approved, making it the first animated film sequel theatrically released by the studio. Following their duties on Oliver & Company (1988), animators Butoy and Gabriel were recruited to direct the sequel. Research trips to Australia provided inspiration for the background designs. The film would also mark the full use of the Computer Animation Production System (CAPS), becoming the first feature film to be completely created digitally. The software allowed for artists to digitally ink-and-paint the animators' drawings, and then composite the digital cels over the scanned background art.