moved forward on production because they were enthusiastic to work with Spielberg. VistaVision cameras installed with motion-control technology were used for the photography of the live-action scenes, which would be composited with animation. Rubber mannequins of Roger Rabbit, Baby Herman, and the Toon Patrol portrayed the animated characters during rehearsals to teach the actors where to look when acting with "open air and imaginative cartoon characters". Many of the live-action props held by cartoon characters were shot on set with the props either held by robotic arms or manipulated with strings, similar to a marionette. For example, a test was shot at ILM with an actor playing the detective would climb down a fire escape and the rabbit is supposed to follow and he knocks down some stacked boxes. Naturally, there would not be a rabbit during the test, so the camera would go down the fire escape and the boxes would fall when a wire was pulled. The actor who played the voice of Roger, Charles Fleischer, insisted on wearing a Roger Rabbit costume while on the set, to get into character. Filming began on November 2, 1986, and lasted for seven and a half months at Elstree Studios, with an additional month in Los Angeles and at Industrial Light & Magic (ILM) for blue screen effects of Toontown. The entrance of Desilu Studios served as the fictional Maroon Cartoon Studio lot. Animation and post-production Post-production lasted for 14 months. ILM had already used 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 cels and optical compositing. 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." 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