Editing Who Framed Roger Rabbit (section)

===Animation and post-production===
[[Post-production]] lasted for 14 months.<ref name="comment" /> ILM had already used [[Computer-generated imagery|CGI]] and [[digital compositing]] in a few movies, such as the stained glass knight scene in ''[[Young Sherlock Holmes]]'', but the computers were still not powerful enough to make a complicated movie like ''Who Framed Roger Rabbit'', so all the animation was done using [[cel]]s and [[Optical printer|optical compositing]].<ref>[https://www.cartoonbrew.com/feature-film/who-framed-roger-rabbit-hits-30-a-look-back-at-ilms-astonishing-old-school-optical-vfx-158471.html ‘Who Framed Roger Rabbit’ Hits 30: A Look Back At ILM’s Astonishing Old-School Optical VFX]</ref><ref name="ears" /> First, the animators and layout artists were given black-and-white printouts of the live-action scenes (known as "photostats"), and they placed their animation paper on top of them. The artists then drew the animated characters in relationship to the live-action footage. Due to Zemeckis' dynamic camera moves, the animators had to confront the challenge of ensuring the characters were not "slipping and slipping all over the place."<ref name="comment" /><ref name="ears" /> Ensuring this did not happen and that the characters looked real, Zemeckis and Spielberg met for about an hour and a half and came up with an idea: "If the rabbit sits down in an old chair, dust comes up. He should always be touching something real."<ref name=":1" /> After the rough animation was complete, it was run through the normal process of traditional animation until the cels were shot on the [[rostrum camera]] with no background. Williams came up with the idea of making the cartoon characters "2.5-dimensional", and the animated footage was sent to ILM for compositing, where technicians animated three lighting layers (shadows, highlights, and tone mattes) separately, to give the characters a sense of depth and create the illusion of them affected by the set lighting.<ref>[https://www.thewrap.com/why-who-framed-roger-rabbit-broke-all-rules-30th-anniversary/ ‘Who Framed Roger Rabbit’ Creators on How They Broke All the Rules]</ref><ref name="ears" /> Finally, the lighting effects were optically composited on to the cartoon characters, who were, in turn, composited into the live-action footage. One of the most difficult effects in the film was Jessica's dress in the nightclub scene because it had to flash [[sequin]]s, an effect accomplished by filtering light through a [[plastic bag]] scratched with [[steel wool]].<ref name="Norman" />