Abstract: Inlet guide structure is provided having complementary outer and inner guides which are adapted to receive film from a drive sprocket of a rolling loop film transport mechanism and to guide the film inwardly towards a path defined between the stator and the rotor of such a mechanism. The outer and inner guides have respective pairs of co-operating side faces for guiding side portions of the film remote from a centre portion of the film. The side faces of the outer guide define a rounded nose portion intermediate ends of these side faces, and the side faces of the inner guide define a depression corresponding to the nose portion so that when in use the guides combine to form a passage which guides the film by contact between the side faces and the side portions of the film.