The infamous growl performed by Christian Bale was much rougher in this film than Batman Begins and has been parodied countless times due to its extreme nature, however the common misconception is that Christian Bale was fully responsible for this voice. The real voice during filming was more toned down and then heightened to a rougher, grittier vibe during post-production under the decision of director Christopher Nolan.

The Joker’s face paint was reportedly designed by Heath Ledger himself, who used white clown makeup and cosmetics from a drugstore. Once his design was approved, the makeup team was responsible for replicating the look each day for filming.

During the chase scene, when the Joker takes over driving after his driver is killed, the bullet holes on the windshield form a smiley face.

Christian Bale got to keep the Batman mask from the movie, after filming.

Heath Ledger directed both homemade videos that the Joker sends to GCN himself. The first video involving the fake Batman was done under Nolan’s supervision. Nolan thought Ledger had done so well with that sequence, he felt there was no need for him to be there when it came time to film the scene where reporter Mike Engel reads the Joker’s statement. He put his trust in Ledger and let him do whatever he wanted, ultimately pleased with the result after he’d seen the outcome.

Christian Bale stated in an interview that during the interrogation scene, Heath Ledger wanted him to beat him as hard as he could to get the real feeling of what was required from the scene.