Ledger, once on board, had a tough job ahead of him -- Jack Nicholson's take on the character was still one of superhero cinema's most iconic villains, and the Australian actor was determined to put his own stamp on The Joker. Ledger used Alex from Stanley Kubrick's "A Clockwork Orange" as an early template of what to aim for, but soon deviated from that, living in a hotel room alone for a month, recording the character's thoughts and feelings in a diary, and working on a voice that proved to be worlds apart from any other interpretation of the character. He also supposedly designed the make up for the character himself, with artist Francis Bacon as an inspiration. Nolan told MSNBC in the lead up to the film's release, "The corrupted clown face is built into the icon of the Joker, but we gave a Francis Bacon spin to it. This corruption, this decay in the texture of the look itself. It’s grubby. You can almost imagine what he smells like.” Costume designer Lindy Hemmings looked more into the music world for her work on the character, taking inspiration from classic '70s punk telling IGN: "You say, 'What's the rationale for him being able to dress like this?' That's when I started looking at the pop world and I ended up looking at the Sex Pistols and Johnny Rotten. I was just thinking, 'Well, there are plenty of guys out there who actually are as extreme as this, and there's nothing wrong with doing it.' You've got to make it look like someone really dresses like this. It can't just be, 'Hello, I'm putting on my costume.' It's got to be wherever he lives and whatever he's been doing, he's been wearing that." Tragically, Ledger wouldn't live to see the acclaim that greeted his performance, passing away of an accidental drug overdose in January 2008, six months before the film's release. But while tabloids tried to ascribe a narrative of a tortured actor sinking too deep into a role, the actor had a blast on the film, telling Empire: "It's the most fun I've had playing a role. I'm really surprised Chris knew I could do it, or thought that I had something in me like this. And I don't know how he came to cast me. But, yeah, it's the bomb. Definitely the most fun I've had, and the most freedom."
Having worked on the first film, both Hans Zimmer and James Newton Howard returned for the follow-up, but were keen to push things further. Zimmer says on the film's Blu-Ray that, "I didn't want to write a summer blockbuster, happy score." While Newton Howard took responsibility for Harvey Dent's themes, Zimmer began playing with less traditional instrumentation for what would become the Joker's main theme, "Why So Serious?" Mid-way through production, Zimmer sent Nolan the results of what he'd been experimenting with, an iPod full of what the director later described as "9000 bars of insanity." Influenced by punk bands like The Damned (with whom Zimmer had worked in the early 1980s), and by Krautrock bands like Kraftwerk, Zimmer's sketches included sounds of playing piano strings with razor blades, and pencils tapping percussively on tables (presumably a reference to the Joker's "magic trick" -- a scene which, incidentally, was responsible for almost half of the complaints that the British Board of Film Certification, who'd given the film a 12A certificate, received in a single year). In the end, Zimmer used two notes, C and D, played on a cello, for the Joker's main theme, combined with an electric guitar played with pieces of metal.
Many directors -- Quentin Tarantino and Martin Scorsese among them -- are well known for asking their actors and collaborators to watch particular films as influences in the run-up to making the film. But Nolan went a little further for "The Dark Knight," blocking out two days in the schedule, not long before the start of principle photography, to screen eight crucial movies for his cast and crew. The first day saw them watch Michael Mann's "Heat," Jacques Tourneur's "Cat People," Orson Welles' "Citizen Kane" and the original 1933 version of "King Kong," while day two started with a refresher screening of "Batman Begins," before John Frankenheimer's "Black Sunday" (good choice!), "A Clockwork Orange," and curiously, Billy Wilder's "Stalag 17." Some of the influences -- Mann and Kubrick's films -- are more obvious than others, but it'd be interesting to do your own marathon viewing of the eight ahead of a rewatch of "The Dark Knight." And we're certainly curious to learn what film Nolan cued up before photography on "The Dark Knight Rises" began. Maybe it's time to let him curate a few days at the New Beverly, or somewhere similar?