A film, also called a movie or motion picture, is a series of still images that, when shown on a screen, create the illusion of moving images. This optical illusion causes the audience to perceive continuous motion between separate objects viewed in rapid succession. The process of filmmaking is both an art and an industry. A film is created by photographing actual scenes with a motion-picture camera; by photographing drawings or miniature models using traditional animation techniques; by means of CGI and computer animation; or by a combination of some or all of these techniques, and other visual effects.
Films were originally recorded onto plastic film through a photochemical process and then shown through a movie projector onto a large screen. Contemporary films are now often fully digital through the entire process of production, distribution, and exhibition. Film is considered to be an important art form, a source of popular entertainment, and a powerful medium for educating—or indoctrinating—citizens. The visual basis of film gives it a universal power of communication.
The individual images that make up a film are called frames. In the projection of traditional celluloid films, a rotating shutter causes intervals of darkness as each frame, in turn, is moved into position to be projected, but the viewer does not notice the interruptions because of an effect known as persistence of vision, whereby the eye retains a visual image for a fraction of a second after its source disappears. The perception of motion is due to a psychological effect called the phi phenomenon.
The name "film" originates from the fact that photographic film (also called film stock) has historically been the medium for recording and displaying motion pictures. The most common term in the United States is movie, while in Europe film is preferred. Common terms for the field in general include the big screen, the silver screen, the movies, and cinema; the last of these is commonly used, as an overarching term, in scholarly texts and critical essays. In early years, the word sheet was sometimes used instead of screen.
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of visual media. Analog and digital variants exist and can be carried on a variety of media, including radio broadcast, magnetic tape, optical discs, computer files, and network streaming.