Trivia: When the taxi Jessica and Eddie are in hits the lamppost, she spins around and her dress shifts position. For a couple of frames on the laserdisc version her underwear vanishes, or at least it appears to. Opinion is divided as to whether it's a deliberate move by the animators or just an error in colouring. (https://www.snopes.com/fact-check/who-stripped-jessica-rabbit/). (00:18:15)
Trivia: Ever wonder what all that technical jargon that Judge Doom rattles off about his "Dip" was all about? The Dip, which he tells Eddie is a mixture he has made out of acetone, benzene, and turpentine, is the only way to kill a toon. Why? Because these are essentially the three main ingredients in "Paint Thinner" - which he uses to literally remove a toon's paint, thereby removing their existence. (00:33:20)
Trivia: A nice subtle detail you might not notice right away - in almost every single scene, Doom's cloak is lightly billowing, as though it has a perpetual breeze running through it. Not only is this a cute nod to the classic cliche of the "billowing cloak" many villains have in comics and cartoons, but it's also a very subtle "hint" that something's not quite right about him.
Trivia: In a bit of irony, Bob Hoskin's live-action character Eddie Valiant had to be animated in a few quick shots during the car-chase with the weasels and Bennie the cab, due to the high-speeds and/or chaotic movement, which would have been too dangerous (or too impractical) to do with Bob Hoskins or a stunt-double. These shots (which actually look fairly creepy, due to Valiant's animated form falling into "uncanny valley") are most easily seen by going frame-by-frame in certain quick shots.
Trivia: The actors who voiced the toons would usually stand off-camera and recite their lines to help the live-action actors with their performances. Charles Fleischer, who voiced Roger Rabbit, had one peculiar demand, though - he asked the production to make him a full-size Roger costume to wear, complete with fur and big, floppy ears. He felt that dressing up in a (ridiculous and hilarious looking) Roger costume would help him get into character every day.
Trivia: They hadn't come up with the final design for Jessica during filming, so Bob Hoskins was told to just imagine his "ideal sexual fantasy" when picturing the character. Hoskins later remarked that the final design was actually sexier and more risque then what he pictured in his head.
Trivia: The first test-screening was a disaster. Most of the cartoon effects were incomplete (with many simply missing), and the crowd was made up entirely of teenagers who weren't told anything about the movie. When the film opened with a cartoon, they began leaving in droves, as they assumed it was a kids' movie. Those who initially stayed started to then walk out due to the film being hard to follow without the effects. However, later tests screenings went much better as more effects were finished.
Trivia: Since Roger's voice actor Charles Fleischer would wear a Roger costume to "get into character," producers and executives from other productions who happened to see him would often mistakenly think he was the actual character that would appear in the final film. Evidently, it was a running joke at the studio for people to talk about "how bad the rabbit movie looks," since they didn't realise the finished film would include an actual cartoon character.