The feasibility of cinema projection from a continuously moving film
H Dennis Taylor · Transactions of the Optical Society · 1924
The paper discusses the optical and mechanical problems involved in the production of screen pictures from a continuously moving film. The film picture may be reflected from a series of mirrors suitably mounted on a drum which is rotated at a definite speed relative to the motion of the film. The various oscillations that may be introduced on the screen image by such projection are discussed, and methods described for minimizing or eliminating them. Calculations are made showing the relation that must exist between the back focal length of the projector lens, the number of mirrors, and the position of stops if definition is to be satisfactory. As compared with the usual type of projection, continuous projection results in a considerable saving of light, much reduced wear and tear of the film, complete freedom from light and dark flickering and consequent eye-strain, and much greater quietness in running.