Film stock is an analog medium that is used for recording motion pictures or animation. It is recorded on by a movie camera, developed, edited, and projected onto a screen using a movie projector. It is a strip or sheet of transparent plastic film base coated on one side with a gelatin emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of the crystals determine the sensitivity, contrast and resolution of the film. The emulsion will gradually darken if left exposed to light, but the process is too slow and incomplete to be of any practical use. Instead, a very short exposure to the image formed by a camera lens is used to produce only a very slight chemical change, proportional to the amount of light absorbed by each crystal. This creates an invisible latent image in the emulsion, which can be chemically developed into a visible photograph. In addition to visible light, all films are sensitive to X-rays and high-energy particles. Most are at least slightly sensitive to invisible ultraviolet (UV) light. Some special-purpose films are sensitive into the infrared (IR) region of the spectrum.
The film industry is built upon many technologies and techniques, drawing upon photography, stagecraft, music, and many other disciplines. Following is an index of specific terminology applicable thereto.
35 mm film is a film gauge used in filmmaking, and the film standard. In motion pictures that record on film, 35 mm is the most commonly used gauge. The name of the gauge is not a direct measurement, and refers to the nominal width of the 35 mm format photographic film, which consists of strips 1.377 ± 0.001 inches (34.976 ± 0.025 mm) wide. The standard image exposure length on 35 mm for movies is four perforations per frame along both edges, which results in 16 frames per foot of film.
Super 8 mm film is a motion-picture film format released in 1965 by Eastman Kodak as an improvement over the older "Double" or "Regular" 8 mm home movie format.
9.5 mm film is an amateur film format introduced by Pathé in 1922 as part of the Pathé Baby amateur film system. It was conceived initially as an inexpensive format to provide copies of commercially made films to home users, although a simple camera was released shortly afterwards.
110 is a cartridge-based film format used in still photography. It was introduced by Kodak in 1972. 110 is essentially a miniaturized version of Kodak's earlier 126 film format. Each frame is 13 mm × 17 mm, with one registration hole. Cartridges with 12, 20, or 24 frames are available on-line. Production variations sometimes have allowed for an additional image.
A movie camera is a type of photographic camera that rapidly takes a sequence of photographs, either onto film stock or an image sensor, in order to produce a moving image to display on a screen. In contrast to the still camera, which captures a single image at a time, the movie camera takes a series of images by way of an intermittent mechanism or by electronic means; each image is a frame of film or video. The frames are projected through a movie projector or a video projector at a specific frame rate to show the moving picture. When projected at a high enough frame rate, the persistence of vision allows the eyes and brain of the viewer to merge the separate frames into a continuous moving picture.
A film recorder is a graphical output device for transferring images to photographic film from a digital source. In a typical film recorder, an image is passed from a host computer to a mechanism to expose film through a variety of methods, historically by direct photography of a high-resolution cathode ray tube (CRT) display. The exposed film can then be developed using conventional developing techniques, and displayed with a slide or motion picture projector. The use of film recorders predates the current use of digital projectors, which eliminate the time and cost involved in the intermediate step of transferring computer images to film stock, instead directly displaying the image signal from a computer. Motion picture film scanners are the opposite of film recorders, copying content from film stock to a computer system. Film recorders can be thought of as modern versions of Kinescopes.
A movie projector is an opto-mechanical device for displaying motion picture film by projecting it onto a screen. Most of the optical and mechanical elements, except for the illumination and sound devices, are present in movie cameras. Modern movie projectors are specially built video projectors.
The Geneva drive is a gear mechanism that translates a continuous rotation movement into intermittent rotary motion.
Film look is a process in which video is altered in overall appearance to appear to have been shot on film stock. The process is usually electronic, although filmizing can sometimes occur as an unintentional by-product of some optical techniques, such as telerecording. The effect is the exact opposite of a process called VidFIRE.
A rotary disc shutter is a type of shutter. It is notably used in motion picture cameras. Rotary shutters are semicircular discs that spin in front of the film gate, alternately allowing light from the lens to strike the film, or blocking it.
A motion picture film scanner is a device used in digital filmmaking to scan original film for storage as high-resolution digital intermediate files.
Mitchell Camera Corporation was a motion picture camera manufacturing company established in Los Angeles in 1919. It was a primary supplier of newsreel and movie cameras for decades, until its closure in 1979.
Film perforations, also known as perfs and sprocket holes, are the holes placed in the film stock during manufacturing and used for transporting and steadying the film. Films may have different types of perforations depending on film gauge, film format, and intended usage. Perforations are also used as a standard measuring reference within certain camera systems to refer to the size of the frame.
Redscale is a technique of shooting photographic film where the film is exposed from the wrong side, i.e. the emulsion is exposed through the base of the film. Normally, this is done by winding the film upside-down into an empty film canister. The name "redscale" comes because there is a strong color shift to red due to the red-sensitive layer of the film being exposed first, rather than last [the red layer is normally the bottom layer in C-41 film]. All layers are sensitive to blue light, so normally the blue layer is on top, followed by a filter. In this technique, blue light exposes the layers containing cyan and magenta dyes, but the layer containing yellow dye is left unexposed due to the filter. E-6 film has also been used for this technique.
A film chain or film island is a television – professional video camera with one or more projectors aligned into the photographic lens of the camera. With two or more projectors a system of front-surface mirrors that can pop-up are used in a multiplexer. These mirrors switch different projectors into the camera lens. The camera could be fed live to air for broadcasting through a vision mixer or recorded to a VTR for post-production or later broadcast. In most TV use this has been replaced by a telecine.
Articles related to the field of motion pictures include:
Multi-image is the now largely obsolete practice and business of using 35mm slides (diapositives) projected by single or multiple slide projectors onto one or more screens in synchronization with an audio voice-over or music track. Multi-image productions are also known as multi-image slide presentations, slide shows and diaporamas and are a specific form of multimedia or audio-visual production.
The history of film technology traces the development of techniques for the recording, construction and presentation of motion pictures. When the film medium came about in the 19th century, there already was a centuries old tradition of screening moving images through shadow play and the magic lantern that were very popular with audiences in many parts of the world. Especially the magic lantern influenced much of the projection technology, exhibition practices and cultural implementation of film. Between 1825 and 1840, the relevant technologies of stroboscopic animation, photography and stereoscopy were introduced. For much of the rest of the century, many engineers and inventors tried to combine all these new technologies and the much older technique of projection to create a complete illusion or a complete documentation of reality. Colour photography was usually included in these ambitions and the introduction of the phonograph in 1877 seemed to promise the addition of synchronized sound recordings. Between 1887 and 1894, the first successful short cinematographic presentations were established. The biggest popular breakthrough of the technology came in 1895 with the first projected movies that lasted longer than 10 seconds. During the first years after this breakthrough, most motion pictures lasted about 50 seconds, lacked synchronized sound and natural colour, and were mainly exhibited as novelty attractions. In the first decades of the 20th century, movies grew much longer and the medium quickly developed into one of the most important tools of communication and entertainment. The breakthrough of synchronized sound occurred at the end of the 1920s and that of full color motion picture film in the 1930s. By the start of the 21st century, physical film stock was being replaced with digital film technologies at both ends of the production chain by digital image sensors and projectors.
