As Christopher Nolan's debut feature, it was designed to be as inexpensive as possible to make: scenes were heavily rehearsed so that just one or two takes were needed, thus economising on 16 mm film stock, the production's greatest expense, and for which Nolan was paying from his salary. Without expensive professional lighting equipment, Nolan mostly used available light. Apart from writing, directing, and photographing the film, Nolan also helped in editing and production.Instead of fighting against the limitations of the production, Christopher Nolan allowed them to dictate everything from the film’s structure, to its handheld shooting style, to the 16mm film it was shot on.. to black-and-white stock and setting the scene during the day and place the characters next to windows or in natural sunlight as much as possible. Nolan has explained it in a detailed interview with VICE.