There are two faces to The Dark Knight’s music, and one is always overlooked

On the occasion of The Dark Knight’s 10th anniversary, Polygon is spending the week investigating the comic-book blockbuster’s legacy. Why so serious? Because Christopher Nolan’s Bat-sequel gave us lots to talk about. This is the retrospective you deserve and the one you need right now.

Music is the most crucial, cohesive element in Christopher Nolan’s Dark Knight trilogy. The score for each film sets the tone: Batman Begins is more operatic, in keeping with its more comic book-esque story and aesthetic; The Dark Knight is sparser and more experimental as the film veers away from superhero fantasy, villain dynamics and traditional story structure; and The Dark Knight Rises score falls between the two, as realism (relatively speaking) and mysticism meet.

Of the three, it’s the score to The Dark Knight that is perhaps the best known, largely for the harsh, glissando of the Joker theme. But there’s much more to it, not least a push and pull between the score’s two composers.

The scores for Batman Begins and The Dark Knight were collaborative efforts between Hans Zimmer and James Newton Howard, who’s best known for composing music for The Sixth Sense, Waterworld, Peter Jackson’s King Kong, and the theme to ER. (Howard bowed out for The Dark Knight Rises.) Speaking about Batman Begins in the past, Zimmer has noted that he and Howard wanted to work together for a long time, and stresses that they collaborated every step of the way. “It’s not like we divided themes up or anything like that,” he said in an interview with IGN. “We really, really worked together on each cue pretty much. I mean there isn’t a single cue that isn’t informed by both of us.”

The Dark Knight, however, seems to be a little more split. Though there are still elements that can’t quite be attributed to one composer or the other — “Nobody will ever know who wrote what tune and what piece,” Zimmer has said — there is a definitive dividing line.

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“Because the characters are so distinct, so clearly defined and so powerful, it was conceivable there could be musical identities attached to each one of them,” Howard said, speaking of the process of composing for The Dark Knight. “[That allowed] Hans and I both to dig in and not only just collaborate on pieces of music, which we often do, but to each separately be working on pieces of music associated with one character or another.”

In other words, the two major new themes present in the film, the Joker’s and Harvey Dent’s, are composed by Zimmer and Howard respectively, instead of being attributable to both at once.

The Joker’s theme in The Dark Knight remains the most often discussed piece of music, and with good reason: it doesn’t sound like anything else. The cue wails and scratches, the product of razor blades sliced along string instruments. As Zimmer says on The Dark Knight DVD, “I wanted to write something people would truly hate.” But that wailing subsides bit by bit as the movie progresses, mixing with and being subsumed by Batman’s theme as the hero catches up.

Harvey Dent’s theme experiences that same shift. It’s harder to track, as it’s more melodious to begin with, but that’s not to diminish its importance. After all, though the film’s central conflict may be between Batman and the Joker, it hinges on Dent’s transformation into Two-Face. The music that accompanies Harvey’s appearances for the first half of the film is much more melodic than even Batman’s, in keeping with his front-facing, “pure” persona.

“I wrote Harvey as an American hero,” Howard said, describing how he focused on brass instruments for Harvey’s orchestrations, and used American composer Aaron Copland as a source of inspiration. As Harvey becomes Two-Face, however, his musical theme becomes darker, becoming slightly less melodic and relying less and less on the bright sound of the brass section.

In a movie this austere, this grand, The Dark Knight’s musicality pushes the human element forward. Nothing in a film score is ever done by accident; even the introduction of the Batman theme at the very end of Batman Begins instead of using it throughout was intentional, meant to signal a transformation of Bruce Wayne. He needed to earn the theme. The shift from more classical sounds in the first film to the experimental, electronic tone in the sequel is also deliberate. To quote Zimmer, “They evolved just the way the world has evolved.”

The space between the Joker and Dent’s respective themes is an aural gradation between the black and white opposites that they represent, meeting in the middle as Batman emerges. It’s mirrored in the composition process; though the rest of the score seems to have been much more collaborative than the way that those two themes were divided, it still would appear that Howard handled more of the “prettier stuff” as Zimmer tackled the action scenes, eventually meeting in the middle as the characters’ storylines — and their respective tones — intersect.

It’s fitting, then, that the music for the final confrontation between Batman and Two-Face has Howard’s touch. It’s a relatively quiet piece, unlike the more driving, anarchic music that plays whenever the Joker is present; again, it’s a “prettier” composition. Like Dent’s original theme, the notes are also constantly rising, yet the brass is gone, replaced by dissonant strings that twist the once-heroic theme into something tragic.

Though Howard credits Zimmer as being the “designated leader” when it came to composing for The Dark Knight, his contributions can’t be overlooked. The idea of balance is a crucial part of The Dark Knight’s narrative, and it’s Howard who provides that in the score. As the composer responsible for musically charting Harvey Dent’s arc, he not only accounts for the way that Batman emerges in the D.A.’s story, but twists Dent’s theme as the character begins to fundamentally change. As the Joker says, “Madness, as you know, is like gravity. All it needs is a little push.”

Though Zimmer’s music hurtles and propels the events of the film towards that tipping point, it’s Howard’s work that tips the balance.

Karen Han is a writer based in New York City. Her work appears on Vox.com, The Atlantic, SlashFilm, and New York magazine’s Vulture.