Cinematography (from , kinema “movements” and γράφειν, graphein “to record”) is the science or art of motion picture photography by recording light or other electromagnetic radiation, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as film stock. Typically, a lens is used to repeatedly focus the light reflected or emitted from objects into real images on the light-sensitive surface inside a camera during a timed exposure creating multiple images. With an electronic image sensor, this produces an electrical charge at each pixel, which is electronically processed and stored in a video file for subsequent display or processing. The result with photographic emulsion is series of invisible latent images on the film stock, which are later chemically “developed” into a visible image. The images on the film stock are played back at a rapid speed and projected on a screen creating the illusion of a movie. Cinematography is employed in many fields of science and business as well as its more direct uses for recreational purposes and mass communication.