In preparation for his role as The Joker, Heath Ledger hid away in a motel room for about six weeks. During this extended stay of seclusion, Ledger delved deep into the psychology of the character. He devoted himself to developing The Joker's every tic, namely the voice and that sadistic-sounding laugh (for the voice, Ledger's goal was to create a tone that didn't echo the work Jack Nicholson did in his 1989 performance as the Joker). Ledger's interpretation of The Joker's appearance was primarily based on the chaotic, disheveled look of punk rocker Sid Vicious combined with the psychotic mannerisms of Malcolm McDowell's character, Alex De Large, from A Clockwork Orange (1971).
Heath Ledger designed the Joker make-up himself, using white clown makeup and cosmetics from a drugstore, reasoning that since the Joker himself would design and apply it, Ledger should do so as well. Once his design was approved, the makeup team was responsible for replicating the look each day for filming.
In Sir Michael Caine's opinion, Heath Ledger beat the odds and topped Jack Nicholson's Joker from Batman (1989): "Jack was like a clown figure, benign but wicked, maybe a killer old uncle. He could be funny and make you laugh. Heath's gone in a completely different direction to Jack, he's like a really scary psychopath. He's a lovely guy and his Joker is going to be a hell of a revelation in this picture." Caine bases this belief on a scene where the Joker pays a visit to Bruce Wayne's penthouse. He'd never met Ledger before, so when Ledger arrived and performed he gave Caine such a fright he forgot his lines.
During the scene where the Joker crashes Bruce Wayne's party for Harvey, when he first appears in the elevator Alfred was meant to have some lines, however this was the first time Michael Caine had seen Heath Ledger with the Joker make up on, you can even see the shocked expression on his face as the Joker walks past him.
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.
Blood is only ever seen three times on-screen: on the face of the civilian Batman that the Joker hangs, on Harvey's pillow in the hospital, and on Batman's arm due to the dog attacking him; most of the violence either occurs off-screen or is obscured by camera angles.
Heath Ledger's sudden death on January 22, 2008 prompted immediate speculation over the film's state. Soon after Ledger's tragic passing was announced, Warner Bros. Pictures issued a statement that verified that Ledger had finished all of his scenes in principal photography, as well as post-production fulfillments (i.e., looping), thus making The Joker his final, completed film role.
While the movie was filming a chase scene on Lake Street, the Chicago Police Department received several calls from concerned citizens stating that the police were involved in a vehicle pursuit with a dark vehicle of unknown make or model.
The character of Reese is an allusion to The Riddler, who attempts to reveal the identity of Batman. Much like Edward Nygma whose name sounds like "enigma" (as in E. Nygma), Mr. Reese sounds like "mysteries".
Trouble arose during a PR campaign before the movie's release,when a website related to the film sent out several cakes purportedly from The Joker, containing a cell phone inside which made the cake vibrate, and had wires sticking out, making the cake look like a bomb. One such news station which received one of the cakes, believed it to be an actual terrorist act, and the entire building had to be evacuated.
Heath Ledger posthumously won a total of 32 Best Supporting Actor awards for his work on this film, including the Oscar, Golden Globe, BAFTA, SAG and Critics' Choice award. The only awards he was nominated for but didn't win were the Satellite Award (which went to Michael Shannon for Revolutionary Road (2008)) and the London Film Critics' Circle Award for actor of the year (which went to Mickey Rourke for The Wrestler (2008)). Both Michael Shannon and Mickey Rourke would later go on to play comic book villains in films of their own; Shannon as General Zod in Man of Steel (2013) and Rourke as Ivan Vanko in Iron Man 2 (2010)
According to Christopher Nolan, Bruce Wayne's reasons for needing a new Batsuit (to be faster and more agile) were, in fact, the real reasons why Nolan wanted the Batsuit to be redesigned for this film.
The bus crashing backwards into the bank in the opening sequence was much harder to pull off than was anticipated. The bus had to be taken apart and reassembled inside the building (a disused post office), concealed behind a large false wall, and then propelled backwards with an air cannon.
The infamous growl performed by Christian Bale was much rougher in this film than Batman Begins (2005) 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.
Despite endless speculation on which actor had been chosen to portray The Joker, Heath Ledger had always been among Christopher Nolan's foremost choices for the role. Ledger & Nolan had met during the Batman Begins (2005) casting process for the role of Bruce Wayne/Batman, but both the director and the actor agreed Ledger was wrong for the part. When casting the part of the Joker, Nolan met with several other actors before Ledger but found them reluctant to take the role because of the popularity of Jack Nicholson's performance in the original Batman (1989). Upon meeting with Ledger again, Nolan recognized him as the perfect choice for the part. When asked the reason for this unexpected casting, Nolan simply replied, "Because he's fearless."
The Batman theme is heard only twice in the film, as composers Hans Zimmer and James Newton Howard decided that a heroic theme that a viewer could hum would overlook the complexity and darkness of the character. Hearing the tune only twice would create what Zimmer calls "a musical foreshadowing."
Many believe that one of the key reasons why the Academy moved from five Best Picture nominations to 10 was because two of the best received films of the year - The Dark Knight (2008) and WALL·E (2008) - were not among the five nominees.
During the Hong Kong action scene (to bring Lau back), Batman shoots time-bombs on the glass which has a time of 2:22 minutes. The bombs explode almost exactly after 2 minutes 20 seconds in real time, which shows that the action could happen in almost 2 minutes.
Bruce Wayne wears a new Batsuit in the film. This Batsuit was an improvement on the outfit from Batman Begins (2005), and made Christian Bale more comfortable and agile in his performance. It was constructed from 200 unique pieces of rubber, fiberglass, metallic mesh, and nylon (producing an impression of sophisticated technology), with elastic banding added for tightening the costume to fit Bale. The gauntlets had their razors made retractable and able to be fired. The suit's cowl was based on a motorcycle helmet and separated from the neck piece, allowing Bale to move his head left/right/up/down, and comes equipped with white eye lenses for when Batman turns on Bat-sonar.
Elaborate, interactive marketing campaigns were launched in the months leading up to the release of this film. One of these was an event at the 2007 San Diego Comic-con called Why So Serious, which involved fans following clues hidden around the city. The legions of Joker-painted fans ended up congregating in the street across from the convention center, where one of their numbers was welcomed into a black Escalade (with Gotham license plates) that had just pulled up. After a moment the fan started screaming and the SUV sped away. Later that day, a Gotham City newspaper was circulated reporting that a man believed to be the Joker was found beaten to death. Included were crime scene photos of the fan who had gotten into the Escalade, and a mention that he was found with a playing card in his hand, on which was scribbled "See you in December."
Whilst filming in Chicago, Wanted (2008) was the neighboring production, and Morgan Freeman worked concurrently on both films. At one point, Wanted comic book writer Mark Millar visited the set but without permission. The security and Lauren Shuler Donner (who also visited the set at that time) caught Millar sitting on the Batpod. Millar was escorted away from the set.
David S. Goyer and Christopher Nolan collaborated on the story of the film. The script itself was written by Nolan and his brother Jonathan Nolan. After watching 'The Dark Knight', Goyer stated "I can't believe my name is on a movie this good".
Aaron Eckhart described his portrayal of Harvey Dent as simultaneously coming from and being apart from the same world as Batman (Dent is the white knight of Gotham, as opposed to the Dark Knight). His challenge was "looking for the similarities and the tension between the two; to find what's similar to Batman and then what's opposite to him." Eckhart prepared for his role by studying split personalities.
The first Batman movie that does not feature Bruce Wayne's mansion, although it is mentioned. This is faithful to the comics in the sense that in the period from 1969 to the early 1980s, Batman had moved out of Wayne Manor and lived in a penthouse. However, that version was on top of his Wayne Foundation building and that building had a secret Batcave below which he could access through a hidden elevator connection to the penthouse.
Aaron Eckhart is technically the third actor to play Harvey Dent/Two-Face in a feature film. Billy Dee Williams played a pre-disfigured Dent in Batman (1989), but he didn't become Two-Face until Batman Forever (1995), where Tommy Lee Jones took the role (in that film, Dent's transformation was briefly shown in a flashback where Batman tried to save him from Boss Maroni, and Harvey was already Two-Face at the beginning). This is the first Batman film to depict Two-Face's origin, starting with Harvey Dent as Gotham's district attorney and eventually becoming Two-Face.
In one draft of the script, a reference to Robin being related to Rachel Dawes was considered. The character of Dick Grayson was not explicitly mentioned, however Rachel Dawes is revealed as being a relative of the Grayson family. Christopher Nolan had it removed because he didn't want to build hopes up about the Robin character appearing in a future film.
In the film, Bruce asks Lucius Fox for a new Batman suit with a head piece that is 'easier to look around in'. This is a comical reference to older Batman films in which the actors playing Batman wore a suit that had a solid head piece covering the head, neck and shoulders. This made it impossible for the actors to turn their heads and instead had to turn their entire torso to look at their targets.
Christian Bale admitted he did not pack on as much muscle weight for this film as he did for Batman Begins (2005), in part due to keeping with the new Batsuit design, which is leaner and more flexible.
Bruce Wayne's penthouse was actually shot on the ground floor of an office building in downtown Chicago. During the daytime the same exact space was re-dressed and used for Harvey Dent's press conference scenes.
When Harvey Dent disarms the witness in court, he removes the magazine from the stock and holds it in his small finger. This is actually the correct procedure for emergency reloads and correcting malfunctions.
The Joker make-up was composed of three pieces of stamped silicone, which took less than an hour to apply to Heath Ledger on each day of shooting. Ledger described it as "new technology which is much quicker to apply than regular prosthetics"; he felt he was not wearing any make-up at all.
When Harvey Dent is being transferred, his holding vehicle is attacked by The Joker with various guns. One gun is an RPG and a SWAT member is heard asking if it is a bazooka - which is a signature weapon of The Joker's girlfriend/partner in crime - Harley Quinn.
According to the British Board of Film Classification (or BBFC), this film received the most complaints of the decade from British viewers. It was the subject of 42 per cent of all letters received by the BBFC in 2008.
Unlike his counterpart in both the comics and Batman (1989), the Joker in this film does not have his hair and flesh permanently bleached by toxic waste. His trademark grin was never definitively identified in the comics as a disfigurement. However, its appearance here, as scars deliberately carved into his flesh, echo the character's original inspiration, the character Gwynplaine from Victor Hugo's novel The Man Who Laughs (1928).
Jerry Robinson, one of the original creators of the Joker back in 1940, was hired as a consultant on the film (the Joker is to be portrayed according to his first two appearances in the comics, which Robinson was involved in). His "Batman" co-creator Bob Kane had earlier been hired as a consultant for Batman (1989).
With 4,366 locations, this film also holds the record for opening in the most venues on its release date. (Pirates of the Caribbean: At World's End (2007) opened in 4,362 movie houses the previous summer.)
Shortly before the film's DVD debut, Warner Brothers were under legal action by the city of Batman, Turkey (pronounced "but-mun") in November 2008. Even though it wasn't used in the title, the character name of Batman was considered an infringement.
In the parking garage, each of the "fake" Batmen is seen firing a gun of some kind. The original creators of the Batman comics decided that Batman would never be shown holding a gun, due to him already bearing so many other similarities to another comic book hero, The Shadow.
The Joker falling from the Prewitt building mirrors a scene from the very first Joker story in 'Batman' #1 (Spring, 1940) in which the Joker falls from a penthouse scaffolding, but is caught by the Batman.
The false title given to the film during production, Rory's First Kiss, was named after Christopher Nolan's son, Rory. When filming began in April 2007, the production was code-named to thwart onlookers and trespassers. All over downtown Chicago, fliers were posted with this pseudonym (alongside an "RFK" logo) and also listed the address for the film's production offices.
The IMAX cameras used in filming proved to be problematic for the crew. Dialog that was recorded on film is very noisy so it had to be replaced during post-production. An IMAX camera is very heavy and it cannot be used hand held. Instead, special mounts had to be created to support the weight. Finally, they had to get the shots right as it takes 5 days to process the negative instead of the conventional negative.
Hong Kong actor Edison Chen can be seen escorting Lucius Fox from the helicopter into the building, and later when the police goes in for the raid at Lau's office. The Hong Kong scene contains a scripted set piece where Batman drops into the harbor. However it was scrapped because environmental officials found out that the water was polluted.
Batman leaps from the roof of Two IFC, the tallest building in Hong Kong at the time, at over 400 meters. Some time later, he appears to be gliding down to the same rooftop. His target is in fact One IFC, which is about half as tall and has a similar ornate crown.
The lenses that cover Batman's eyes during the hostage rescue scene give him a look that's close to the comic and animated adaptations, where Batman's eyes are often visible in the dark while the rest of his body is blacked out.
The console for the Bat Sonar resembles "The Listening Post", Mark Hasen and Ben Rubin's dynamic portrait of online communication, especially when Lucius Fox and Batman switch it off. The installation is currently on display at the Science Museum in London.
This film held the box-office record for the largest opening weekend of all time. It made $158,411,483 in its first weekend of release. Another superhero sequel, Spider-Man 3 (2007), set the record the previous summer. Dark Knight held it until the release of Harry Potter and the Deathly Hallows: Part 2 (2011) which had an opening weekend of $169,189,427, which was later beaten by The Avengers (2012) (another superhero movie) with $200.3 million. This is the fourth Batman movie to break the opening weekend record following Batman (1989), Batman Returns (1992), and Batman Forever (1995).
For the first time in feature filmmaking, IMAX cameras were utilized. Christopher Nolan had wanted to shoot in the IMAX format for years, thus using this film as his opportunity to do so. Six major action-heavy sequences, along with various high-altitude shots, were filmed on the IMAX ratio. (These sequences are available on the Bonus Disc of the 2-Disc DVD Edition.)
When it was released on July 18, 2008, this film made $67.2 million in a single day, the most lucrative opening for any film. Because of its pent-up demand, midnight showings all over the country were sold out, resulting in $18.5 million in late-night showings alone. The movie held the record for biggest one-day intake until The Twilight Saga: New Moon (2009).
On Thanksgiving weekend, 2007, fake four-page tabloid-size Gotham Times newspapers were distributed at various public events. Headlined "City at War - Batman Saves Entire Family," every article teased events in the film, and everything in the handout was geared toward the film, including the weather ("Gloomy and overcast...") and advertisements for Gotham National Bank, the Gotham Girl Guides and recruitment for the Gotham Police Department.
Nestor Carbonell, who plays the mayor, coincidentally also played "Bat Manuel", a parody of Batman, in the comic-based live action The Tick (2001) TV series. Michael Jai White who played the Batman-inspired character Spawn in Spawn (1997) plays a gangster.
Batman asks Alfred to find the names of any police officers who have family members staying in the hospital. Alfred texts Gordon with two names "Ramirez, Berg". Charles Ramirez-Berg is an acclaimed professor of radio-television-film at the University of Texas at Austin who, among other honors, was mentioned in Robert Rodriguez 's autobiography as his favorite professor.
IMAX camera technician/consultant Wayne Baker has a cameo that is the only close up shot in the IMAX format in the film. He sits on the loading dock and reacts to the Batpod emerging from the wreckage of the Batmobile.
Lower Wacker Drive in Chicago was closed every night starting at 7 PM during the summer of 2007 to accommodate filming. The street was open during the day, however, and the several Batmobiles and tumblers were visible just on the other side of the barricades covered only with sheets.
An explosion was filmed at the Battersea Power Station in London. The fireball created calls from panic-stricken local residents, who assumed a terrorist attack had occurred at the out-of-use station. The Battersea Power Station first received popularity after being featured on the front cover of Pink Floyd's 1977 album "Animals". (A pig is seen flying over the power station.)
Near the beginning of the movie, there is a scene where Batman pauses at the top of a parking garage, looking down a spiraling entrance ramp at an escaping van and planning the exact time to jump. Christian Bale does this exact same thing with a chainsaw in a spiraling staircase in American Psycho.
Heath Ledger kept licking his lips because the way he speaks during his performance requires him to have a moist mouth. Many people say it was a habit of his own before hand (which it was) however he ensured he did it 'a lot more to keep his performance consistent'
While filming both the bank and police department scenes at the post office, an unrelated fire broke out in a top floor mechanical room and many onlookers believed that the smoke and fire was related to the filming.
'The Dark Knight' on Blu-ray disc features the IMAX version of the film. Any sequence filmed with the IMAX cameras fills up a widescreen TV at a 1:78:1 ratio, thus giving a grander view from the top to bottom. The rest of the film plays at a 2:35:1 scope ratio which delivers a panoramic view. It is only on Blu-ray that the film can be watched this way as on a 4:3 TV the transition would be too jarring, however the IMAX sequences can be viewed as a special feature on the DVD version.
Sean Penn was Christopher Nolan and the Warner Bros first choice for the role of the joker but he turned down the part because he didn't want to play a role who have played by his longtime friend Jack Nicholson.
Along with Anatomy of a Murder (1959), Crimson Tide (1995), and Independence Day (1996), this is one of only four films whose purely orchestral soundtracks won the Grammy Award for Best Score despite not being nominated for an Academy Award for Best Original Score.
The serrated edges on the side of the Batman's gauntlets were inspired by the pulp character Tony Quinn, the Black Bat, whose origin (he was a district attorney victim of an acid flinging gangster) was borrowed for Two-Face.
Gotham City's civic heraldry combines elements of New York City's and Chicago's municipal emblems. Examples include Gotham-area license plates (based on Illinois tags found throughout Chicago) and Gotham's garbage trucks (whose door emblems directly quote New York City's old Sanitation Department logo: a large red sans-serif capital letter S atop a medical caduceus, all within a circle with a text border).
The ferries depicted are CGI models of the Molinari-class of Staten Island Ferry. The Staten Island Ferry, which is run by the New York Department of Transportation, offers a free 25-minute ride across New York harbor from St. George in Staten Island to South Ferry in Manhattan.
35mm VistaVision cameras were used to provide additional coverage of some of the action sequences as there were only a limited number of Imax cameras available. Though rarely used since the 1960's, the format provides a larger frame area than regular 35mm and is horizontally-gated in the same manner as 65mm Imax.
When it was announced that the Joker would be main antagonist in the film it was rumoured that Paul Bettany would be playing the part, however when Heath Ledger was cast Christopher Nolan came under criticism from the media as they thought Ledger was completely wrong for the role.
Actor/musician Dwight Yoakam turned down two different roles in this film. One was for the part of Det. Wuertz (later played by Ron Dean), as well as the small part of the Gotham National Bank manager (portrayed by William Fichtner) featured at the very beginning.
A conspiracy theorist proposed that this iteration of The Joker is a heavily-traumatized veteran of the War on Terror, hence his "truckload of soldiers" line and his skill with multiple types of firearms.
The Bat Symbol at the beginning of each film in the trilogy foreshadows something that happens later. In this case the Bat Symbol is made up of fire and it symbolizes Harvey Dent's face being burned which later turns him into Two-Face.
When Rachel Dawes and Harvey Dent are on a date, and Bruce Wayne comes there with a lady, whom he introduces as 'Natasha'; 'Natasha' is the name of Sir Michael Caine's (The actor who plays Alfred J. Pennyworth) real-life daughter.
The older gentleman that confronts the Joker at the party thrown by Bruce Wayne for Harvey Dent. Senator Leahy is a huge Batman fan and arranged an early showing of the movie on July 12th as a fund-raiser for the children's section of the Kellogg-Hubbard Library in Montpelier, Vermont, the state's capital. He has also appeared in Batman & Robin (1997) and as a Batman: The Animated Series (1992) cartoon voice.
Buster Reeves, Christian Bale:
a Joker thug. He appears in the trailer of the Joker's semi-truck, as he hands The Joker his weapons as he fires them at the police transport. He then rides in the passenger seat of the cab of the truck as The Joker drives.
Heath Ledger improvised when he started clapping inside his jail cell in a mocking and sardonic way as Gordon is promoted. The clapping was not scripted, but Christopher Nolan immediately encouraged the crew to continue filming and the sequence was included in the film.
When Harvey holds the Joker at gunpoint in the hospital scene, you can see that the Joker is actually holding the revolver's hammer with his finger, thus preventing the shot in case Harvey's coin lands on "bad" side.
The address 250 52nd Street where Rachel Dawes is killed, and where Harvey Dent brings Gordon's family is a palindrome: it's the same forwards as it is backwards. The way it's framed with a zero in the middle and the same numbers in opposite directions on either side suggests the opposite sides of Dent's favorite coin, the two sides of his face, and by extension the duality of his nature.
In one of the final scenes of the film where Harvey flips his coin for Batman, himself, and Gordon, the outcome of the flips foreshadows the future of each of the 3 characters. Batman received "Tails," the "bad" side; at the end of the film he asked Gordon to blame all of the city's troubles on him, resulting in the Batman's reputation being disgraced and scorned. On the other hand, both Gordon and Harvey received "Heads," the "good" side, and were both honored as heroes at the end of the film.
Two-Face's disfigurement was created through computer graphics rather than prosthetic make-up, as director Christopher Nolan felt that, no matter how good the make-up was, it is still inherently adding something onto an actor's face, when Two-Face's appearance requires part of his face to be burned away.
The Joker only looks at three of the people he kills in the film. He shoots the bus driver while looking back at the hostages. Two of Gambol's thugs he stabs while looking up. He kills Gambol while looking at another thug. He throws the cigar lighting Lau on fire and turns to talk to The Chechen as Lau dies. The three he looks at are the thug he kills with a pencil, the policeman stopping the semi-truck before the chase, and the policeman that is clearing the hospital out which he shoots with a pistol while in a nurse uniform. This character choice is a reference to the graphic novel 'The Man Who Laughs' in which it is mentioned that The Joker "just opened fire and didn't even look at the people while he killed them".
There are many elements from various Batman graphic novels, either verbatim or slightly recast. In The Long Halloween, Batman, Gordon, and Dent fake Dent's death; in The Dark Knight, Gordon's death is faked. Also in The Long Halloween, Batman poses as a SWAT officer; in the movie, Gordon does. The Joker's reference at the end of the film to pushing Dent over the edge mirrors his social experiment with Gordon in The Killing Joke, in which The Joker attempts to drive Gordon insane by making him have a really bad day. A lot of the interaction between Batman and The Joker is taken from The Long Halloween, specifically the interrogation scene in the film, which is also is similar to elements of The Dark Knight Returns. The copycat Batmen are clearly inspired by The Sons of The Batman from The Dark Knight Returns. Finally, in The Killing Joke, the Joker explains if he "had a past, it would be multiple choice." This is referenced when the Joker tells two different stories about the origin of his scars.
Aaron Eckhart enjoyed wearing the Two-Face makeup and warned: "When you look at him, you should get sick to your stomach. 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 drawn versions of what they think it looks like, and I can tell you this: They're thinking small. Chris has gone way farther than people think."
The film uses numerous elements of the Joker's first appearance in Batman #1, published in 1940. In both The Dark Knight and Batman #1, the Joker publicly announces his crimes before committing them, removes his make-up and disguises himself as a police officer to gain access to a person he threatened to kill, uses a powerful bomb smuggled into jail to escape, steals and kills not for personal gain but simply to create chaos and disorder, and infringes upon the city's old-fashioned mobsters.
The infamous interrogation scene originally ended with Batman, after getting the information he needs from the Joker and dropping him on the ground, quickly kicking the Joker in the head right before he leaves to save Rachel, almost as an afterthought. However, this part was removed in editing because director Christopher Nolan felt the action seemed "a little too petulant for Batman".
Bruce Wayne makes his final appearance in the film (out of the batsuit) a whole forty minutes before the end of the movie, when he is reacting to the sound of Gotham General Hospital exploding shortly after his car accident.
In the original Batman comics (specifically, Detective Comics #80, 1943) the surname of the plastic surgeon who attempts to repair Two-Face is "Ekhart". In this movie, Two-Face is, of course, played by Aaron Eckhart.
After his transformation, Two-Face flips his coin eight times. It comes up on the good side five times for the Joker, Sal Maroni, Detective Ramirez, Dent himself, Gordon's son (though Two-Face didn't catch that one) and the bad side three times, for Detective Wuertz, Maroni's driver and Batman.
Early in the film, a witness on stand pulls a gun out on Harvey Dent (Two-Face) during the trial and tries to shoot him. This is a nod towards Two-Face's original origin story in the comics where in a similar trial scenario, crime boss Sal Maroni is on stand and throws sulfuric acid in Dent's face resulting in his scarring.
This is the only film in the Dark Knight trilogy that there is not a surprise revelation as to who was the instigator of the criminal events and the identity of a villain. This is also the only film in the trilogy where the League of Shadows does not play an active part in the plot.
The camera angle shooting up at The Joker as he beats Batman with a pipe is reflective of the graphic novel scene in the Batman series 'A Death In The Family', in which The Joker kills Robin (Jason Todd) with a crowbar.
In this film, despite his name, Joker only performs two actions that could pass for jokes...the pencil trick, and his faux-seductive greeting to Harvey Dent while in the nurse's outfit. [He also claps sardonically when Gordon is appointed Commissioner of Police, and throws his hands up in mock despair when the hospital he targets (Gotham General) doesn't immediately go up in flames.]
Harvey Dent's first official appearance is in a courthouse where he's prosecuting Salvatore Maroni and is threatened by a witness. This is an echo to Batman lore where Harvey Dent had acid tossed into his face by a witness during a trial. This, coupled with a deep seated mental illness, is what triggered his transformation into Two-Face.
All of the main action in this film takes place over nine days and nights, by far the shortest time span of the Dark Knight Trilogy (Batman Begins takes place over decades, and The Dark Knight Rises - even when removing the flashbacks that elongate its time span to decades - still covers many months within the main action). The only scenes in the film that are implied to take place outside of these nine days and nights are the brief flash-forwards in the final scene of Harvey Dent's funeral (which would probably not take place for at least one week) and Gordon breaking the bat signal. The "day" with the most screen time in the film is the final day, which covers forty-eight minutes (a full third of the total runtime). Furthermore, unlike the other films of the trilogy, which contain copious flashbacks, this film only contains one flashback, when Harvey Dent remembers flipping his coin to Rachel while lying in his hospital bed. With that flashback, The Dark Knight not only becomes the only film in the trilogy where Bruce Wayne does not have a flashback, but also the only film where the content of the flashback references a previous scene within the film's main action. The flashbacks of the other films all either reference moments that take place outside of the film's main action (e.g. a flashback to Wayne's childhood), or moments that, while being part of the main action, are shown for the first time in the flashback.