Batman had two soundtracks: one a score by Danny Elfman, the other an album Prince wrote just for the movie. Initially contracted to write just two songs, Prince ended up falling in love with the movie and knocking out an LP's worth. Burton later wrote that he "couldn't make the [Prince] songs work, and I think I did a disservice to the movie and to him."
The process of building the perfect Batsuit required the construction of 28 models, along with 25 capes and six cowls. Because the cowl was attached to the cape, it didn't allow him to move his head, giving rise to a move called the “Bat Turn,” which required Keaton to move his whole body along with his head.
After the stress of shooting Batman, Burton wasn’t keen on making a sequel. In order to convince him, Warner Bros. handed over increased creative control. Burton gave Sam Hamm’s script to Heathers writer Daniel Waters with the instruction to cleanse the script of all signs that Batman Returns was a sequel. That included removing Vicki Vale, deleting revelations about Jack Napier, and scraping mentions of Batwing scraps being sold as souvenirs in Gotham.
Burgess Meredith, who played the Penguin in the TV version of Batman, was initially supposed to play Oswald Cobblepot’s father. He wasn’t available because of an illness, so Paul Reubens of Pee-wee Herman fame was given the role.
Robin Williams had long been the leading candidate to play the Riddler should the character ever make it into a movie. Ultimately Williams turned down the role because he thought it wasn't as comedic as the version Frank Gorshin played in the sixties TV series.
One of Schumacher's most controversial changes in Batman Forever was adding nipples to the Batsuit, an idea he got from statues of Greek gods. The nipples went over poorly with many Batfans. More important, Jim Carrey says the nipples "pissed off Bob Kane," the creator of Batman who worked as a consultant on the film.
Batman & Robin
From the outset of Batman & Robin, Warner Bros. pushed Schumacher to make a more family-friendly film, and the studio allowed toy companies to be involved in the production. Schumacher says that the studio asked for the movie to be “toyetic, which means that what you create makes toys that can sell." Toy companies didn’t just get advance designs of costumes, vehicles, and weapons either; they helped develop them.
Uma Thurman beat out Julia Roberts and Demi Moore to play Poison Ivy. Patrick Stewart and Anthony Hopkins were considered for Mr. Freeze before Schumacher decided the maniac needed to be a pumped-up giant. So he asked Arnold Schwarzenegger to play the part and told him if he said no, the movie would have to find a new director.
The studio’s next attempt to revive Batman involved the Man of Steel. Wolfgang Peterson was hired to direct Batman vs. Superman and Se7en writer Kevin Walker wrote a screenplay. Peterson said the movie would pit a brooding, big city Batman against an innocent, small-town Superman and provide "a true existential experience with visual fun." Studio politics doomed the mash-up and Warner Bros. decided to prioritize a Superman movie instead.
As with all the previous Batman movies, the Batsuit was redesigned for Batman Begins. Among the significant advancements was a new cowl that allowed Batman to turn his head, along with a cooling system that allowed Bale to stay in the suit for longer periods of time. The new cape also represented a significant advancement. After experimenting with velvet, costume designer Lindy Hemming and her team invented a new fabric made of parachute nylon and velvet pile that had an animal-like look but was light enough to fly. She also borrowed a technique called electrostatic flocking from the British Ministry of Defense that gave the cape a flowing, billowing effect.
Nolan shied away from using CGI whenever possible, even attempting to use real bats on the set. That lasted one day. Dead bats were scanned digitally to create the computer images and proved much easier to handle than the real things.
The Dark Knight
While Bale did speak in a bearlike growl when dressed as Batman, much of the bizarre gravelly effect of his voice in The Dark Knight was added in postproduction.
Composer Hans Zimmer set out to create the Joker's signature sound without retreading stock villain music. He started experimenting with razor blades on piano wire and pencils tapping on the floor. Ultimately the sound he settled on hinged on playing two conflicting notes on a cello then adding in a guitar part played with a piece of metal.