Traditionally, films were recorded onto celluloid film through a photochemical process and then shown through a movie projector onto a large screen. Contemporary films are often fully digital through the entire process of production, distribution, and exhibition, while films recorded in a photochemical form traditionally included an analogous optical soundtrack (a graphic recording of the spoken words, music and other sounds that accompany the images which runs along a portion of the film exclusively reserved for it, and is not projected).
