Direct-on-film animation refers to any imagery created on film without a camera. An interchangeable term is "cameraless animation." Since the days of the direct-on-film pioneers Norman McLaren and Len Lye, the medium has evolved from a method of special effects to a broad range of artistic expression. The work of the four artists I interviewed illustrate the wide range of processes that can be considered direct-on-film animation from straightforward drawing and painting on film frame by frame, to altering the film's surface with chemicals.
Bosworth, Leah, "Film Alchemy: Interviews with Direct-On-Film Animators" (1994). Milne Library Faculty/Staff Works. 2.