computer-generated imaging where practical effects would not suffice. Production designer Nathan Crowley designed the Batpod (Batcycle) because Christopher did not want to extensively re-use the Tumbler. Corbould's team built the Batpod, which is based on a prototype Crowley and Christopher built by combining different commercial model components. The unwieldy, wide-tired vehicle could only be ridden by stuntman Jean Pierre Goy after months of training. The Gotham General Hospital explosion was not in the script but added during filming because Corbould believed it could be done. Hemming, Crowley, Christopher, and Jamie Rama re-designed the Batsuit to make it more comfortable and flexible, developing a costume made from a stretchy material covered in over 100 urethane armor pieces. Sculptor Julian Murray developed Dent's burnt-facial design, which is based on Christopher's request for a skeletal appearance. Murray went through designs that were "too real and more horrifying" before settling on a more "fanciful" and detailed but less-repulsive version. Hemming designed Joker's overall appearance, which he based on fashion-and-music celebrities to create a modern and trendy look. Influence also came from the 1953 painting Study after Velázquez's Portrait of Pope Innocent X by Francis Bacon—suggested by Christopher— and the character's comic-book appearances. The outfit consists of a purple coat, a green vest, an antique shirt, and a thin, 1960s-style tie that Ledger suggested. Prosthetics supervisor Conor O'Sullivan created Joker's scars, which he partly based on a scarred delivery man he met, and used his own technique to create and apply the supple, skin-like prosthesis. John Caglione Jr designed Joker's "organic" makeup to look as though it had been worn for days; this idea was partly based on more of Bacon's works. Caglione Jr used a theatrical makeup technique for the application; he instructed Ledger to scrunch up his face so different cracks and textures were created once the makeup was applied and Ledger relaxed. Ledger always applied the lipstick himself, believing it was essential to his characterization. Music Composers James Newton Howard and Hans Zimmer, who had also worked on Batman Begins, scored The Dark Knight because Christopher believed it was important to bridge the musical-narrative gap between the films. The score was recorded at Air Studios, London. Howard and Zimmer composed the score without seeing the film because Christopher wanted them to be influenced by the characters and story rather than fitting specific on-screen elements. Howard and Zimmer separated their duties by character;