For his conception of the film, Nolan was inspired by the Joker's first two appearances in the comics and Batman: The Long Halloween. The Dark Knight was filmed primarily in Chicago (as was Batman Begins), as well as in several other locations in the United States, the United Kingdom, and Hong Kong. The director used an IMAX camera to film six major action sequences, including the Joker's first appearance in the film. The Batsuit was redesigned, with a cowl allowing Bale to move his head. The film also introduces a recreation of the Batcycle, known as the Batpod.
The Dark Knight opens with Batman, Lieutenant James Gordon, and new district attorneyHarvey Dent beginning to succeed in rounding up the criminals that plague Gotham City. They are unexpectedly challenged when a mysterious criminal mastermind known as the Joker appears in Gotham. Batman's struggle against the Joker becomes deeply personal, forcing him to "confront everything he believes" and to improve his technology to stop the madman's campaign of destruction. During the course of the film, a love triangle develops between Bruce Wayne, Dent and Rachel Dawes.
Christian Bale as Bruce Wayne / Batman: A billionaire who has dedicated himself to protecting Gotham City from the criminal underworld. Bale was confident in his choice to return in the role because of the positive response to his performance in Batman Begins. He trained in the Keysi Fighting Method, and performed many of his own stunts. He did not gain as much muscle this time, because of the storyline in which Batman builds a new suit that allows him to move with more agility.
The actor described Batman's dilemma as whether "[his crusade is] something that has an end. Can he quit and have an ordinary life? The kind of manic intensity someone has to have to maintain the passion and the anger that they felt as a child, takes an effort after awhile, to keep doing that. At some point, you have to exorcise your demons." He added, "Now you have not just a young man in pain attempting to find some kind of an answer, you have somebody who actually has power, who is burdened by that power, and is having to recognize the difference between attaining that power and holding on to it." Bale felt because Batman's personality was strongly established in the first film, it was unlikely that his character would be overshadowed by the villains, stating: "I have no problem with competing with someone else. And that's going to make a better movie."
Heath Ledger as The Joker: Heath Ledger described the Joker as a "psychopathic, mass murdering, schizophrenic clown with zero empathy". Nolan had wanted to work with Ledger on a number of projects in the past, but had been unable to do so.  When Ledger saw Batman Begins, he realized a way to make the character work in that film's tone, and Nolan agreed with his anarchic interpretation. To prepare for the role, Ledger lived alone in a hotel room for a month, formulating the character's posture, voice and psychology. While he initially found it difficult, Ledger was eventually able to generate a voice that did not sound like Jack Nicholson's take on the character in Tim Burton's1989 Batman film. He started a diary, in which he wrote the Joker's thoughts and feelings to guide himself during his performance. He was also given Batman: The Killing Joke and Arkham Asylum: A Serious House on Serious Earth to read, which he "really tried to read [...] and put it down". Ledger also cited inspirations such as A Clockwork Orange and Sid Vicious, which were "a very early starting point for Christian [Bale] and I. But we kind of flew far away from that pretty quickly and into another world altogether.” "There’s a bit of everything in him. There’s nothing that consistent," Ledger said, adding that "There are a few more surprises to him."
Before Ledger was confirmed to play the Joker in July 2006,Paul Bettany,Lachy Hulme,Adrien Brody,Steve Carell, and Robin Williams publicly expressed interest in the role. On not being invited to reprise the part, Jack Nicholson said: "You can't believe the reasons things do or don't happen. Not asking me how to do the sequel is that kind of thing. ... Maybe it's not a mistake. Maybe it was the right thing, but to be candid, I'm furious." After the first official trailer was released, director Guillermo del Toro and comic book writer Jeph Loeb praised Ledger's portrayal of the character, while Batman: The Animated Series co-creator Paul Dini said, "He seems more street than any other version of the Joker. ... His attitude is mordant and sardonic as opposed to manic. ... No goofy gags or puns for him. This Joker doesn't split sides: he splits skulls."Mark Hamill, who voiced the part on Batman: The Animated Series, said "The balls-out debauched psycho approach seems like a great way of reinventing everyone’s favorite scary (and scar-y) clown."
After filming had already ended, Ledger died, on January 22, 2008, leading to intense press attention and memorial tributes. In March 2008, four months prior to the film's scheduled release, Larry Carroll reported that "like Batman himself, Christian Bale, Maggie Gyllenhaal and director Christopher Nolan find themselves shifting gears between being secretive, superheroic and fighting back a deep sadness." "It was tremendously emotional, right when he passed, having to go back in and look at him every day," Nolan recalled. "But the truth is, I feel very lucky to have something productive to do, to have a performance that he was very, very proud of, and that he had entrusted to me to finish." Nolan has dedicated the film to Ledger's memory. All of Ledger's scenes were completed on set, and there will be no digital manipulation to complete his performance (unlike Oliver Reed in Gladiator).
Aaron Eckhart as Harvey Dent / Two-Face: The Gotham district attorney; Dent's battle with the Joker turns Dent into a murderous, disfigured vigilante called "Two-Face". Producer Charles Roven described Dent as initially the "white knight of the city". Wayne sees Dent as his heir, which comes back to the theme of him realizing that being Batman will be a lifelong mission, and the tragedy that follows when Dent is corrupted. Whereas Two-Face is an evil villain in the comics, Nolan chose to portray him as a twisted vigilante to emphasize his role as Batman's counterpart, and Eckhart, who has played corrupt men in films such as The Black Dahlia, Thank You For Smoking and In the Company of Men, notes: "[He] is still true to himself. He's a crime fighter, he's not killing good people. He's not a bad guy, not purely," while admitting: "I'm interested in good guys gone wrong." Nolan and David S. Goyer had originally considered using Dent in Batman Begins, but they replaced him with the new character Rachel Dawes when they realized they "couldn’t do him justice". Before Eckhart was cast in February 2007, Liev Schreiber,Josh Lucas, and Ryan Phillippe had expressed interest in the role. Nolan chose Eckhart, whom he had considered for the lead role in Memento, citing his "extraordinary" ability as an actor, his embodiment of "that kind of chiselled, American hero quality" projected by Robert Redford, and his subtextual "edge".
Maggie Gyllenhaal as Rachel Dawes: The Gotham assistant D.A. and childhood friend of Bruce Wayne, she is one of the few people who know that he is Batman. Gyllenhaal has acknowledged that her character is a damsel in distress to an extent, adding that Nolan had sought ways to empower her character so that "Rachel's really clear about what's important to her and unwilling to compromise her morals, which made a nice change" from the many conflicted characters whom she has previously portrayed. In August 2005, before the casting of Gyllenhaal, producer Charles Roven had reported that actress Katie Holmes (who portrayed Rachel Dawes in Batman Begins) was going to reprise the role in The Dark Knight; however, in January 2007, Holmes turned down the offer to reprise her role as Rachel Dawes due to scheduling conflicts, and, by March 2007, Gyllenhaal was in "final talks" for the part.
Before the release of Batman Begins, screenwriter David S. Goyer wrote a treatment for two sequels, which introduced the Joker and Harvey Dent, and whose original intention was that the Joker would scar Dent during his trial in the third film, turning him into Two-Face. When asked about those roles, Nolan has explained that, in developing a film, he does not think "in terms of sequels .... I think in terms of making this film the best film it can be and the most complete film it can be." Goyer, who wrote the first draft of the screenplay, cites the DC Comics 13-issue comic booklimited seriesBatman: The Long Halloween as the major influence on his conception of the storyline. While initially unsure of whether the Joker would return, Nolan did want to reinterpret the Joker on screen. After much research, his brother and co-writer Jonathan suggested the Joker's first appearance in the two first issues of Batman as the crucial influence.Jerry Robinson, one of the Joker's co-creators, was consulted about the character's portrayal. Nolan decided to avoid having to tell an in-depth origin story for the character, portraying his rise to power instead. He explained, "To me, the Joker is an absolute. There are no shades of gray to him [...] He bursts in just as he did in the comics."
"As we looked through the comics, there was this fascinating idea that Batman's presence in Gotham actually attracts criminals to Gotham, [it] attracts lunacy. When you're dealing with questionable notions like people taking the law into their own hands, you have to really ask, where does that lead? That's what makes the character so dark, because he expresses a vengeful desire."
—Nolan on the theme of escalation
On July 31, 2006, Warner Bros. Pictures officially announced the initiation of production for the sequel, titled The Dark Knight. This makes it the first live-action Batman film without the word "Batman" in its title, which Bale noted as signaling that "this take on Batman of mine and Chris' is very different from any of the others." Nolan described the sequel's theme as escalation, continuing how Batman Begins ended, with "things having to get worse before they get better". The director indicated that the film will continue the themes of Batman Begins, including justice vs. revenge and Bruce Wayne's issues with his father, but it would also show more of Batman as a detective, an element which they did not have time to convey in Batman Begins. He described the friendly rivalry between Bruce Wayne and Harvey Dent as the "backbone" of the film. Nolan has cited Heat, the 1995 film directed by Michael Mann starring Robert De Niro and Al Pacino, as well as some other films, as "sort of an inspiration" in the film's attempt "to tell a very large, city story or the story of a city".
While scouting for shooting locations in October 2006, location manager Robin Higgs visited Liverpool, concentrating mainly along the city's waterfront. Other candidates included Yorkshire, Glasgow, and parts of London. In August 2006, one of the film's producers, Charles Roven, stated that its principal photography would begin in March 2007, but filming was pushed back to April. For its release in IMAX theaters, Nolan shot four major action sequences in that format, including the Joker's introduction, and said that he wished that it were possible to shoot the entire film in IMAX: "if you could take an IMAX camera to Mount Everest or outer space, you could use it in a feature movie." For fifteen years Nolan had wanted to shoot in the IMAX format, and he used it also for "quiet scenes which pictorially we thought would be interesting."
Warner Bros. chose to film in Chicago for 13 weeks, because Nolan had had a "truly remarkable experience" filming part of Batman Begins there. While filming in Chicago, the film was given the false title "Rory's First Kiss" to lower the visibility of production, but the local media eventually uncovered the ruse. As The Guardian observes, Richard Roeper of The Chicago Sun-Times commented on the absurdity of the technique, "Is there a Bat-fan in the world that doesn't know 'Rory's First Kiss' is actually 'The Dark Knight', which has been filming in Chicago for weeks?" Production of The Dark Knight in Chicago generated $45 million in the city's economy and created thousands of jobs. For the film's prologue involving the Joker, the crew shot in Chicago from April 18 to April 24, 2007. They returned to shoot from June 9, 2007 to early September.
Heath Ledger as the Joker. The Joker's scruffy and grungy make-up is intended as a reflection of his "edgy" character.
Costume designer Lindy Hemming described the Joker's look as reflecting his personality — that "he doesn't care about himself at all"; she avoided designing him as a vagrant but still made him appear to be "scruffier, grungier", so that "when you see him move, he's slightly twitchier or edgy." Nolan noted, "We gave a Francis Bacon spin to [his face]. This corruption, this decay in the texture of the look itself. It's grubby. You can almost imagine what he smells like." In creating the "anarchical" look of the Joker, Hemming drew inspiration from such counterculturalpop culture artists as Pete Doherty, Iggy Pop, and Johnny Rotten. During the course of the film, the Joker never removes his make-up, causing it to become more unkempt and resemble an infection as it worsens. Ledger described his "clown" mask, made up of three pieces of stamped silicone, as a "new technology", much quicker to apply than regular prosthetics, and he felt that he was barely wearing any make-up at all. It took only an hour for the make-up artists to apply to Ledger's face.
Designers improved on the design of the Batsuit from Batman Begins, adding wide elastic banding to help bind the costume to Bale, and suggest more sophisticated technology. It was constructed from 200 individual pieces of rubber, fiberglass, metallic mesh, and nylon. The new cowl was modeled after a motorcycle helmet and separated from the neck piece, allowing Bale to turn his head left and right and nod up and down. The cowl is equipped to show white lenses over the eyes when the character turns on his sonar detection. The gauntlets have retractable razors which are able to be fired. The gloves also possess hydraulics for Batman to crush objects. The original suit will also be worn during part of the film. Though the new costume is eight pounds heavier, Bale found it more comfortable and less hot to wear.
The film introduces the Batpod, which is a recreation of the Batcycle. Crowley, who designed the Tumbler for Batman Begins, designed six models (built by Chris Corbould) for use in the film's production, because of necessary crash scenes and possible accidents. Crowley built a prototype in Nolan's garage, before six months of safety tests were conducted. The Batpod is steered by shoulder instead of hand, and the rider's arms are protected by sleeve-like shields. The bike has 508 millimeter (20-inch) front and rear tires, and is made to appear as if it is armed with grappling hooks, cannons, and machine guns. The engines are located in the hubs of the wheels, which are set 3 1/2 feet (1067 mm) apart on either side of the tank. The rider lies belly down on the tank, which can move up and down in order to dodge any incoming gunfire that Batman may encounter. Stuntman Jean-Pierre Goy doubled for Christian Bale during the riding sequences in The Dark Knight.
For Two-Face's make-up, Eckhart warned, "When you look at [him], you should get sick to your stomach. Being the guy under all that, well, that was a lot of fun for me. It's like you would feel if you met someone whose face had pretty much been ripped off or burned off with acid [...] There are fans on the Internet who have done artist's versions of what they think it will look like, and I can tell you this: They're thinking small; Chris is going way farther than people think."
The depiction of Gotham City is less gritty than in Batman Begins. "I've tried to unclutter the Gotham we created on the last film," said production designer Nathan Crowley. "Gotham is in chaos. We keep blowing up stuff. So we can keep our images clean."
Batman Begins composers Hans Zimmer and James Newton Howard returned to score the sequel. Zimmer originally said the main Batman theme was purposely introduced at the end of Batman Begins, and would be fleshed out in the sequel as the character develops. Zimmer and Howard both realized that creating a heroic theme that a viewer could hum would ignore the complexity and darkness of the character. That the heroic theme is audible only twice, early on in the film, creates what Zimmer described as a "red herring", a kind of musical foreshadowing.
Their eight-minute suite for the Joker is based around two notes. Zimmer compared its style to the band Kraftwerk, who come from his native Germany, as well as his work with bands like The Damned. When Ledger died, Zimmer felt like scrapping and composing a new theme, but decided that he could not be sentimental and compromise the "evil [the performance] projects". Howard composed Dent's "elegant and beautiful" themes, which would work as a contrast.
In May 2007, 42 Entertainment began a viral marketing campaign utilizing the film's "Why So Serious?" tagline with the launch of a website featuring the fictional political campaign of Harvey Dent, with the caption, "I Believe in Harvey Dent." The site aimed to interest fans by having them try to earn what they wanted to see and, on behalf of Warner Bros., 42 Entertainment also established a "vandalized" version of I Believe in Harvey Dent, called "I believe in Harvey Dent too," where e-mails sent by fans slowly removed pixels, revealing the first official image of the Joker; it was ultimately replaced with many "Haha"s and a hidden message that said "see you in December."
WhySoSerious.com directed fans to find letters composing the Joker's message "The only sensible way to live in this world is without rules," to send in photographs of these letters, and then featured their photos in a collage.
During the 2007 Comic-Con International, 42 Entertainment launched WhySoSerious.com, sending fans on a scavenger hunt to unlock a teaser trailer and a new photo of the Joker. During that month, WhySoSerious.com featured an animated jack-o'-lantern whose mouth was shaped like a bat-logo. The candle in the jack-o'-lantern melted as time progressed, while half of the pumpkin's face simultaneously deteriorated.
On October 31, 2007, the film's website morphed into another scavenger hunt with hidden messages, instructing fans to uncover clues at certain locations in major cities throughout the United States, and to take photographs of their discoveries. The clues combined to reveal a new photograph of the Joker from the film, accompanied by an audio MP3 clip of Ledger's recorded voice saying, "And tonight, you're gonna break your one rule." Completing the scavenger hunt also led to another website called Rory's Death Kiss, where fans could submit photographs of themselves costumed as the Joker set in various landscapes. Those who sent photos were mailed a copy of a fictional newspaper called The Gotham Times, whose electronic version led to the discovery of numerous other websites.
The Dark Knight's opening sequence, (showing a bank raid by the Joker) and closing montage of other scenes from the film, was screened with selected IMAX screenings of I Am Legend, which was released on December 14, 2007. A theatrical teaser was also released with non-IMAX showings of I Am Legend, and also on the official website. The sequence will be released on the Blu-ray Disc edition of Batman Begins on July 8, 2008.
After the death of Heath Ledger, on January 22, 2008, Warner Bros. adjusted its promotional focus on the Joker. It revised some of its websites dedicated to promoting the film, posting a memorial tribute to Ledger on the film's official website and overlaying a black memorial ribbon on the photo collage in WhySoSerious.com. On February 29, 2008, I Believe in Harvey Dent was updated to enable fans to send their e-mail addresses and phone numbers. In March 2008, Harvey Dent's fictional campaign informed fans that actual campaign buses nicknamed "Dentmobiles" would tour various cities to promote Dent's candidacy for district attorney.
The Dark Knight has been met with wide critical acclaim. Peter Travers of Rolling Stone gave The Dark Knight 3.5 out of 4 stars, calling the film "haunting and visionary" and commenting that it "soars on the wings of untamed imagination". He particularly praised Nolan and Ledger, who he suggested could get a posthumousAcademy Award nomination. Larry Carroll, a film news writer for MTV Networks, praised the cinematography and described it as "the best Batman movie ever made.Emanuel Levy gave the film an A, stating the film is "nothing short of brilliant" and "the best and scariest comic hero adaptation you are likely to see this summer season, and perhaps during the whole year." Film director Kevin Smith was astounded by the film, declaring it "an epic", "The Godfather II of comic book movies", and "close to a masterpiece". Todd Gilchrist of IGN gave the film a 10/10 and 5 stars stating that "Nolan's sequel surpasses the original with an intense, disturbing masterpiece".