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.
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.
Digital intermediate (DI) is a motion picture finishing process which classically involves digitizing a motion picture and manipulating the color and other image characteristics.
Color grading is a post-production process common to filmmaking and video editing of altering the appearance of an image for presentation in different environments on different devices. Various attributes of an image such as contrast, color, saturation, detail, black level, and white balance may be enhanced whether for motion pictures, videos, or still images. Color grading and color correction are often used synonymously as terms for this process and can include the generation of artistic color effects through creative blending and compositing of different layer masks of the source image. Color grading is generally now performed in a digital process either in a controlled environment such as a color suite, and is usually done in a dim or dark environment.
In photography, reversal film or slide film is a type of photographic film that produces a positive image on a transparent base. Instead of negatives and prints, reversal film is processed to produce transparencies or diapositives. Reversal film is produced in various sizes, from 35 mm to roll film to 8×10 inch sheet film.
In photography, a negative is an image, usually on a strip or sheet of transparent plastic film, in which the lightest areas of the photographed subject appear darkest and the darkest areas appear lightest. This reversed order occurs because the extremely light-sensitive chemicals a camera film must use to capture an image quickly enough for ordinary picture-taking are darkened, rather than bleached, by exposure to light and subsequent photographic processing.
A contact print is a photographic image produced from film; sometimes from a film negative, and sometimes from a film positive or paper negative. In a darkroom an exposed and developed piece of film or photographic paper is placed emulsion side down, in contact with a piece of photographic paper, light is briefly shone through the negative or paper and then the paper is developed to reveal the final print.
Photographic printing is the process of producing a final image on paper for viewing, using chemically sensitized paper. The paper is exposed to a photographic negative, a positive transparency , or a digital image file projected using an enlarger or digital exposure unit such as a LightJet or Minilab printer. Alternatively, the negative or transparency may be placed atop the paper and directly exposed, creating a contact print. Digital photographs are commonly printed on plain paper, for example by a color printer, but this is not considered "photographic printing".
Compositing is the process or technique of combining visual elements from separate sources into single images, often to create the illusion that all those elements are parts of the same scene. Live-action shooting for compositing is variously called "chroma key", "blue screen", "green screen" and other names. Today, most, though not all, compositing is achieved through digital image manipulation. Pre-digital compositing techniques, however, go back as far as the trick films of Georges Méliès in the late 19th century, and some are still in use.
Bleach bypass, also known as skip bleach or silver retention, is a chemical effect which entails either the partial or complete skipping of the bleaching function during the processing of a color film. By doing this, the silver is retained in the emulsion along with the color dyes. The result is a black-and-white image over a color image. The images usually have reduced saturation and exposure latitude, along with increased contrast and graininess. It usually is used to maximum effect in conjunction with a one-stop underexposure.
Techniscope or 2-perf is a 35 mm motion picture camera film format introduced by Technicolor Italia in 1960. The Techniscope format uses a two film-perforation negative pulldown per frame, instead of the standard four-perforation frame usually exposed in 35 mm film photography. Techniscope's 2.33:1 aspect ratio is easily enlarged to the 2.39:1 widescreen ratio, because it uses half the amount of 35 mm film stock and standard spherical lenses. Thus, Techniscope release prints are made by anamorphosing, enlarging each frame vertically by a factor of two.
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.
The original camera negative (OCN) is the film in a traditional film-based movie camera which captures the original image. This is the film from which all other copies will be made. It is known as raw stock prior to exposure.
An internegative is a motion picture film duplicate. It is the color counterpart to an interpositive, in which a low-contrast color image is used as the positive between an original camera negative and a duplicate negative.
In cinematography, bipacking, or a bipack, is the process of loading two reels of film into a camera, so that they both pass through the camera gate together. It was used both for in-camera effects and as an early subtractive colour process.
Color motion picture film refers both to unexposed color photographic film in a format suitable for use in a motion picture camera, and to finished motion picture film, ready for use in a projector, which bears images in color.
Eastmancolor is a trade name used by Eastman Kodak for a number of related film and processing technologies associated with color motion picture production and referring to George Eastman, founder of Kodak.
A release print is a copy of a film that is provided to a movie theater for exhibition.
Dufaycolor is an early British additive colour photographic film process, introduced for motion picture use in 1932 and for still photography in 1935. It was derived from Louis Dufay's Dioptichrome plates, a glass-based product for colour still photography, introduced in France in 1909. Both Dioptichrome and Dufaycolor worked on the same principles as the Autochrome process, but achieved their results using a layer of tiny colour filter elements arrayed in a regular geometric pattern, unlike Autochrome's random array of coloured starch grains. The manufacture of Dufaycolor film ended in the late 1950s.
Eastman Color Positive (ECP) is a photographic processing system created by Kodak in the 1950s for the development of monopack color positive print for direct projection motion picture film stock. It is part of the Eastmancolor family of products sold by Kodak.
