Black-Light Motion-Picture Photography

a method of motion-picture photography that uses the luminescence of phosphors. In the production of motion pictures black-light photography is used mainly to produce frame sequences in which an object appears to hang in space (for example, space vehicles, rockets, and airplanes used as part of a set). For such a purpose the objects are colored with dyes containing phosphors as additives; during the filming, the objects are illuminated by mercury-quartz lamps with filters that pass only ultraviolet light. As a result the exposed film shows only the luminescent object; supports, suspensions, and the background do not appear in the picture. A second exposure can be used to photograph the back-ground, and a wide variety of pictorial effects may be produced by methods of combined projection.

Another version of black-light motion-picture photography produces films with enhanced brightness or color contrast. To produce such an effect, certain components of the scenery, props, or costumes, as well as puppets or drawings (in animated cartoons), are painted with phosphors that emit light of the required color when excited by rays of visible light. Illumination by white light increases the color intensity and brightness of the painted components. If the luminescence of a phosphor results from excitation by radiation of certain wavelengths, effects such as the “sparkling” of jewels or “flashing” of a dragon’s eyes may be produced by intermittent irradiation.