|Glossary of Film / Video Terms (A-G)|
1D LUT: A 1-dimensional lookup table is a static color translation table that converts one input value to one output value. There is a 1-to-1 correspondence in the input and output values in a 1D LUT.
16 mm: The frame is one-fourth the size of a 35 mm frame and has a 1.33:1 television aspect ratio. The film can have perforations on both sides or on just one side. When compared to 35 mm, grain is more apparent.
2K: A digital image 2048 pixels wide. A standard 2K scan of a full 35 mm film frame is 2048 X 1556 pixels.
3:2 Pull-down: The telecine transfer relationship of film frames to video fields. Film shot at 24 fps is transferred to 30 fps NTSC video with an alternating three-field/two-field relationship.
3D LUT: A 3-dimensional lookup table is a static color translation table that converts a set of three input color values to another set of three output color values.
35 mm: The standard gauge for professional filmmakers, and the standard mainstream film format used for theatrical releases.
4K: A digital image 4096 pixels wide. A standard 4K scan of a full 35 mm film frame is 4096 X 3112 pixels.
65 mm: The camera film format (size) for wide-screen formats such as IMAX.
70 mm: The release print format (size) for wide-screen formats such as IMAX.
A Wind: When you hold a roll of 16 mm or other single-perf film so that the film leaves the roll from the top and toward the right, the perforations will be along the edge toward the observer.
Abrasion Marks: Scratches on film caused by dirt, improper handling, grit, emulsion pileups, and certain types of film damage (e.g., torn perforations).
Academy Aperture: In projection, the aperture cutout, designed as specified by the American Academy of Motion Picture Arts and Sciences that provides for a screen-image aspect ratio of approximately 1.37:1; also called "sound aperture."
Acetate: Actually cellulose triacetate, the base material frequently used for motion picture films. Also, in sheet form, for overlay cells.
Acetate-Base Film: Any film with a support that contains cellulose triacetate; safety film.
Acquisition: General term used to describe the input of media for the DI process. All source media during acquisition must be digitized or transferred digitally.
Additive Color: Color mixture by adding light from any of the three primaries: red, green, and blue.
Algorithm: A procedure to perform a task. Given an initial state, an algorithm will produce a defined end-state. Computer algorithms are used to perform image-processing operations.
Aliasing: A digital artifact consisting of patterns or shapes that have no relation in size and orientation with those found in the original image. This is often caused by too low a scan resolution or sampling rate. The best solution is to acquire the image at a sufficient sampling rate or use an anti-aliasing algorithm.
Analog: A recording technique (for video or audio) that is continuously variable (as opposed to digital, which is either on or off using 1's and 0's).
Anamorphic: An optical system having different magnifications in the horizontal and vertical dimensions of the image. Basically, special camera lenses squeeze the image horizontally at the time of exposure. This 2-to-1 squeeze uses as much of the negative available and still allows room for an optical sound track on the release print. The print is un-squeezed by the projector lens, which gives the characteristic wide screen (2.35:1) aspect ratio.
ANSI: American National Standards Institute.
Answer Print: The first print (combining picture and sound, if a sound picture), in release form, offered by the laboratory to the producer for acceptance. It is usually studied carefully to determine whether changes are required prior to printing the balance of the order.
Antihalation Backing (Coating): A dark layer coated on or in the film to absorb light that would otherwise be reflected back into the emulsion from the base.
Aperture: (1) Lens: The orifice, usually an adjustable iris, which limits the amount of light passing through a lens. (2) Camera: In motion picture cameras, the mask opening that defines the area of each frame exposed. (3) Projector: In motion picture projectors, the mask opening that defines the area of each frame projected.
Artifacts (Digital Artifacts): Undesirable and unintentional defects in a digital image. Artifacts are often a result of image processing.
ASA: Stands for American National Standards Institution, now International Standards Organization. Exposure Index or speed rating that denotes the film sensitivity. Actually defined only for black-and-white films, but also used in the trade for color films.
Aspect Ratio: Proportion of picture width to height. Some common aspect ratios include 1.85:1 (Acadamy Standard), 2.39:1 (Anamorphic), 1.78:1 (HD), and 1.33:1 (SD).
Asset Management: Managing, tracking, and storing data throughout the entire digital intermediate process.
Average Gradient: A measure of contrast of a photographic image, representing the slope of a portion of a characteristic curve. The term that refers to a numerical means for indicating the contrast or the photographic image.
B Wind: When you hold a roll of 16 mm or other single-perf film so that the film leaves the roll from the top and toward the right; the perforations will be along the edge away from the observer.
Backing: Coating: (e.g. anti-abrasion coating, anti-curl, or remjet backing) applied to the base side of the film to improve characteristics and performance.
Banding: Smooth graduated colors reduced to larger blocks of color. This produces a visible stepping of shades in the image.
Base: The transparent, flexible support, commonly cellulose triacetate (in motion picture cameras), on which photographic emulsions are coated to make photographic film.
Base Plus Fog: Density of the film support plus the silver or dye produced by the effects of the developer. Pertains only to an unexposed portion of the film.
Bell And Howell Perforation (BH): A film perforation shaped with flat top, flat bottom, and curved sides.
Bit: Binary digit, the smallest unit of digital information a computer can work with.
Bit Depth: The number of possible color values used in a digital image. A higher bit depth improves the tonality of an image because there are more color values to choose from.
Bitmap (Raster Image): A digital image formed by pixels mapped on a grid. Each pixel has its own color or grayscale value.
Black-And-White Film: A film that produces a monochromatic picture in shades of gray (usually a metallic silver image).
Bleach: (1) Converting a metallic silver image to a halide or other salt that can be removed from the film with hypo. When bleaching is not carried to completion, it is called reducing. (2) Any chemical reagent that can be used for bleaching.
Blowdown: Reducing a larger format to a smaller format. An example of blowing down would be going from Super 16 down to 16 mm.
Blowup: Occurs when a smaller film format is increased to a larger format. An example would be going from Super 16 up to 35 mm.
CCD (Charged Coupled Device): A chip with a fixed arrangement of sensors that convert light into electrical current. Each electrical current is in proportion to the amount of light hitting each sensor on the CCD. The electrical current is converted to digital data to create a digital image.
Calibration: Sets each device in the post-production pipeline to a specific standard. Calibration ensures all devices acquire, display, and output an accurate image.
Camera Log: A record sheet giving details of the scenes photographed on a roll of original negative.
Camera Original: Film exposed in a camera.
Cellulose Triacetate: Also referred to as "acetate." A transparent, flexible material used as a base support for photographic emulsions.
Characteristic Curve: Shows the relationship between the exposure of a photographic material and the image density produced after processing.
Check print: Used to check the quality of the bulk release work, these are made from the duplicate negative.
Cinch Marks: Short scratches on the surface of a motion picture film which run parallel to its length. These are caused by dust or other abrasive particles between film coils or improperly winding the roll, which allows one coil of film to slide against another.
Cinching: Practice of pulling the end of a film roll to tighten it. It's not recommended.
CINEMASCOPE: Trademark name of a system of anamorphic wide-screen presentation, the first commercially successful anamorphic system for the presentation of wide-screen pictures combined with stereophonic sound. The 35 mm negative camera image is compressed horizontally by 50 percent using a special anamorphic camera lens. Upon projection, the 35 mm print image is expanded horizontally by the same amount using a similar anamorphic projection lens. Depending on the type of sound used in the print, the screen image has an aspect ratio of 2:35:1 (optical sound), or 2:55:1 (4-track magnetic sound).
Circle of Confusion (CoC): The Circle of Confusion characterizes the degree of acceptable focus. The smaller the circle of confusion is, the higher the resulting image sharpness and narrower the depth of field. Traditionally, CoC's of 0.001" for 35mm formats and 0.0005" for 16mm formats are used. With modern, higher contrast, sharper lenses and finer film grains, smaller CoC's may be desired since a smaller resulting spot on the film is reproducible.
Color Analyzer: A device for determining the correct printing light ratios for printing color negatives.
Color Balance: The perceptual appearance of a color image of film as a function of the ratio of exposures of each of the primary color records on the film.
Color Channel: An RGB image is comprised of three different color channels: red, green, and blue. Each channel acts as a layer that stores tonal information. All three channels combined create the colors in the digital image.
Color Correction: The altering of the color balance by modifying the ratio of the printing light values.
Color Correction (Digital Color Grading): Process of adjusting the color and look of images in digital post-production. Digital color correction allows far more control than tradition color timing.
Color Film: Carries one or more emulsions, sensitive to different colors, and forming corresponding dye colors during processing.
Color Internegative: Negative-image color duplicate made from a positive color original. Typically used for making release prints.
Color Management: Use of appropriate hardware, software, and procedures to achieve consistent color throughout the entire digital post-production pipeline.
Color Negative: A negative (opposite) record of the original scene. Colors are complementary to the colors in the scene; light areas are dark, and dark areas are light.
Color Negative Film: Film that after processing has a color negative image. The most common film used.
Color Positive: A positive record of the original scene.
Color Print Film: Film designed for making positive prints from color originals and color duplicates.
Color Reproduction: Refers to the hue quality of rendered colors. This can include color accuracy (in memory colors or in various flesh tones), color preference, flesh-to-neutral reproduction, and tone-scale neutrality.
Color Reversal Film: Film that after processing has a color positive image. Can be an original camera film or a film in which other positive films are printed.
Color Saturation: A term used to describe the brilliance or purity of a color. When colors present in a film image are projected at the proper screen brightness and without interference from stray light, the colors that appear bright, deep, rich, and undiluted are "saturated."
Color Sensitivity: Portion of the spectrum to which a film is sensitive. The ability of the eye or photographic stock to respond to various wavelengths of light.
Color Separation Negative: Black-and-white negative made from red, green, or blue light from an original subject or from positive color film.
Color Space: The range of colors a system is able to reproduce. Digital intermediate work is typically done in the RGB color space.
Color Temperature: The color quality expressed in degrees Kelvin (K)-of the light source. The higher the color temperature, the bluer the light; the lower the temperature, the redder the light.
Color Timing: A laboratory printing process whereby the negative is graded for color and density. A color timer uses a color analyzer to look at and adjust the colors of every scene in the movie. The analyzer has controls for each of the three primary colors: red, green and blue, and overall density.
Colorist: Colorists are artists who work closely with the filmmaker to color correct the film. They help the filmmaker achieve the overall "look" they desire. Using their knowledge of color, they establish continuity between shots and make color decisions that support the story.
Complementary Color: Color that is minus one of the primary colors. Cyan is minus red-cyan and red are complementary colors; yellow is minus blue-yellow and blue are complementary colors; magenta is minus green-magenta and green are complementary colors. A color that produces white when mixed in equal parts with the primary color to which it is complementary.
Composite Print: A print of a film that contains both picture and sound track. Films regularly shown in theaters are composite prints. Also called Release Print.
Composition: The distribution, balance, and general relationship of masses and degrees of light and shade, line, and color within a picture area.
Compression: Algorithms that discard or reorganize information to reduce file size. Compression reduces the amount of storage space and bandwidth needed for images in the digital intermediate.
Conform: Match the original film to the final edited work print.
Conforming (Auto-conforming): Matching the digital intermediate to the final edit. Special conforming software is used to auto conform the digital intermediate by using an edit decision list or a film cut list provided by the editor.
Contact Print: Print made by exposing the receiving material in contact with the original. Images are the same size as the original images, but have a reversed left-to-right orientation.
Continuous Contact Printer: A printing machine where the emulsion of the negative film is in direct physical contact with the positive raw stock emulsion, and the two films are moving continuously across the printing aperture.
Contrast: (1) The general term for describing the tone separation in a print in relation to a given difference in the light-and-shade of the negative or subject from which it was made. Thus, "contrast" is the general term for the property called "gamma" (Y), which is measured by making an H & D Curve for the process under study. (2) The range of tones in a photographic negative or positive expressed as the ratio of the extreme opacities or transparencies or as the difference between the extreme densities. This range is more properly described as "scale" or "latitude." (3) The ability of a photographic material, developer, or process as a whole to differentiate among small graduations in the tones of the subject.
Control Strip: A short length of film containing a series of densities to check on laboratory procedures.
Cross Process: Shooting color reversal film but processing as a color negative film, resulting in an "alternate" look.
Curl: A defect of a photographic film consisting of unflatness in a plane cutting across the width of the film. Curl may result from improper drying conditions, and the direction and amount of curl may vary with the humidity of the air to which the film is exposed.
Curve (H&D): The characteristic curve developed by Hurter and Driffield that depicts how faithfully a photographic emulsion has reproduced the tonal scale of the original scene.
Cyan: Blue-green; the complement of red or the minus-red subtractive used in three-color processes.
D-Log E: (Density vs. the log of Exposure) The graph made by plotting the density of a film sample against the log of the exposure that made that density. Also known as D-Log H, H and D, and characteristic curve. D-Log H (H for exposure) is the technically correct term.
D Log H Curve: The curve showing the relation between the logarithm of the exposure and the resultant density on processed film. Also called the characteristic curve.
D-Max: See Maximum Density.
D-Min: See Minimum Density.
Dailies: Picture and sound work prints of a day's shooting; usually an untimed one-light print made without regard to color balance. Produced so that the action can be checked and the best takes selected; usually shown before the next day's shooting begins.
Daylight: Light consisting of a natural combination of sunlight and skylight (approximately 5500 degrees K).
Definition: The clarity or distinctness with which detail of an image is rendered. Fidelity of reproduction of sound or image.
Densitometer: Instrument used to measure the optical density of an area in a processed image by transmittance (for films) or by reflectance (for photographic prints).
Densitometry: Science of measuring the light-stopping characteristics of film or filters.
Density: Light-stopping characteristics of a film or a filter. The negative logarithm to the base ten of the transmittance (or reflectance) of a sample.
Depth of field: The distance range between the nearest and farthest objects that appear in acceptably sharp focus. Depth of field depends on the lens opening, the focal length of the lens, and the distance from the lens to the subject.
Development: Process of making a visible film image from the latent image produced during exposure.
Developer: A solution used to turn the latent image into a visible image on exposed films.
Diffuse RMS Granularity: The objective measurement of grain.
Digital: A system whereby a continuously variable (analog) signal is broken down and encoded into discrete binary bits that represent a mathematical model of the original signal.
Digital Cinema Distribution Master (DCDM): Digital content that conforms to specifications set by the Digital Cinema Intiatives (DCI). The DCDM is a set of digital files that include images, audio, subtitles and other auxiliary data.
Digital Intermediate: A project in its digital state between input and final output. The digital intermediate goes through many different processes such as digital retouching, digital color grading, integration of visual effects and titling. Therefore, the term "digital intermediate" refers to the digital data's transitional nature-a state between the input stage and final delivery.
Digital Master: Final digital version with all changes in the image processing stage applied. It is used to create all distribution formats, including film, digital cinema, HD, SD, and DVD.
Digital Paint: Software tools and techniques to fix imperfections in digital images.
Digitization (Digitize): process of sampling and converting a continuously variable (analog) signal into discrete mathematical representation of that signal.
Dissolve: An optical or camera effect in which one scene gradually fades out at the same time that a second scene fades in. There is an apparent double exposure during the center portion of a dissolve sequence where the two scenes overlap.
Double-System Sound Recording: Includes a film camera and a separate device, such as a DAT, for audio. For accuracy, the camera should be synced with the sound device and the frame rate should be a constant 24 frames per second. Sound is later transferred to magnetic film and synchronized with picture in postproduction.
Downrezzing (Downsampling): Resizing a digital image to a smaller size.
DPX (Digital Picture Exchange) File: The most common file format used in digital post-production. The DPX format is an ANSI and SMPTE standard. The format provides a great deal of flexibility because it is easy to share between workstations, equipment, and facilities.
Dupe, Dupe Negative: A second generation internegative made from a master positive by printing and development or from an original negative by printing followed by reversal development.
Dust-Busting: Removal of visible dust and scratches after film has been digitized.
Dynamic Range : The range of values between the darkest and brightest perceptible points in an image.
Dye: In photography, the result of color processing in which the silver grains or incorporated color couplers have been converted into the appropriate dye to form part of the color image.
ECN-2: Process for color negative films.
ECP-2: Process for color print films.
Edge Numbers: Numbers on edges of film that identify the film; used to help match original film and sound to edited workprints. Latent-image edge numbers are put on by the manufacturer, and appear during development. Printed edge numbers are placed on the film by the lab, and can be coded for all materials so that any number of picture and sound rolls will have the same sequence. See also KEYKODE.
Edgewax: Waxing method recommended for lubricating release prints; treatment is with a solution of 50 grams of paraffin wax per litre of trichloromethane applied only to the edges of the emulsion side of the film.
EDL (Edit Decision List): List of edits prepared on a non-linear editor in timecode.
Emulsion, Emulsion Layer: (1) Broadly, any light-sensitive photographic material consisting of a gelatin emulsion containing silver halides together with the base and any other layers or ingredients that may be required to produce a film having desirable mechanical and photographic properties. (2) In discussions of the anatomy of a photographic film, the emulsion layer is any coating that contains light sensitive silver halide grains, as distinguished from the backing, base, substratum, or filter layers.
Emulsion Number: A number identifying a complete coating from a single emulsion batch or mixture.
Emulsion Side: The side of a film coated with emulsion.
Emulsion Speed: The photosensitivity of a film, usually expressed as an index number based on the film manufacturer's recommendations for the use of the film under typical conditions of exposure and development.
ESTAR Base: The trademark name applied to the polyethylene terephthalate film base manufactured by Eastman Kodak Company.
Exposure: Amount of light that acts on a photographic material; product of illumination intensity (controlled by the lens opening) and duration (controlled by the shutter opening and the frame rate).
Exposure Index (EI): Number assigned to a film that expresses its relative sensitivity to light. The EI is based on the film emulsion speed, a standard exposure technique, and specific processing solutions.
Exposure Latitude: Degree to which film can be underexposed or overexposed and still yield satisfactory results.
Exposure Meter, Incident: A meter calibrated to read and integrate all the light aimed at and failing on a subject within a large area. (Scale may be calibrated in footcandles or in photographic exposure settings.)
Exposure Meter, Reflectance: A meter calibrated to read the amount of light, within a more restricted area, reflecting from the surface of a subject or an overall scene. (Scale may be calibrated in footcandles or in photographic exposure settings.)
Exposure Setting: The lens opening selected to expose the film.
f -Number: A symbol that expresses the relative aperture of a lens or f/stop. For example, a lens having a relative aperture of 1.7 would be marked f /1.7. The smaller the f-number, the more light the lens transmits.
Fast: (1) Having a high photographic speed. The term may be applied to a photographic process as a whole, or it may refer to any element in the process, such as the optical system, emulsion, developer. (2) Resistant to the action of destructive agents. For example, a dye image may be fast to light, fast to heat, or fast to diffusion.
Ferrotyping: Shiny, blotches on the surface of processed film; caused by heat and/or moisture combined with pressure.
Film Base: Flexible, usually transparent, support on which photographic emulsions are coated.
Film Code: (or product code) is the four-digit number that the film manufacturer assigns to every film product, e.g. 5201.
Film Cut List: List containing KEYKODE Numbers that communicates what frames from the original negative should be included in the conformed negative (traditional) or digital intermediate (digital post).
Film Gate: Components that make up the pressure and aperture plates in a camera, printer, or projector.
Film Identification Code: Letter which identifies film type.
Film Perforation: Holes punched at regular intervals for the length of film, intended to be engaged by pins, pegs, and sprockets as the film is transported through the camera, projector, or other equipment.
Film Sensitivity: The ability of a photographic emulsion to form a latent image when exposed to light.
Film Speed: See "Emulsion Speed."
Final Cut: Last editing of a workprint before conforming is done or before sound workprints are mixed.
Fine Grain: Emulsion in which silver particles are very small.
First Print: The first trial composite (married) print containing both picture and sound for the purpose of checking picture and sound quality.
Fixing: The removal of unexposed silver halides from the film during processing.
Flashing: Technique for lowering contrast by giving a slight uniform exposure to film before processing.
Flat: An image is said to be "flat" if its contrast is low. Flatness is a defect that does not necessarily affect the entire density scale of a reproduction to the same degree. Thus, a picture may be "flat" in the highlight areas, "flat" in the shadow regions, or both.
Flesh-to-Neutral Reproduction: A function of a film's tone-scale neutrality and linearity and its color reproduction. A good performer will offer a neutral tone scale from black to white when flesh tones are balanced to an accurate or preferred position, and vice versa-when flesh tones look reasonable when the film's gray scale is balanced to neutral.
Focal Length: The distance from the optical center of a lens to the point at which parallel rays of light passing through it converge (the focal point).
Fog: Darkening or discoloring of a negative or print, or lightening or discoloring of a reversal material. Causes include accidental exposure to light or x-rays, overdevelopment, using outdated film, and storing film in a hot, humid place.
Footage Numbers: Also called edge numbers or KEYKODE. Sequential numbers which are pre-exposed or printed in ink at regular intervals on the edge of the film outside or in between the perforations.
Force-Process: Develop film for longer than the normal time to compensate for underexposure. More commonly called "push process."
Format: The size or aspect ratio of a motion picture frame.
FPM: Feet Per Minute, expressing the speed of film moving through a mechanism.
FPS: Frames Per Second, indicating the number or images exposed per second.
Frame (film): The individual picture image on a strip of motion picture film.
Frame (video): A complete television picture made up of two fields, produced at the rate of approximately 29.97 Hz (color), or 30 Hz (black & white).
Frame Counter: An indicator that shows the exact number of frames exposed.
Frame Line Marking: A mark placed on the edge of the film between every fourth perforation as an aid to splicing in frame when no image or frame line is visible. On 70 mm film, a small punched hole placed between every fifth perforation.
Frame-Index Marker: (35 mm only) Hyphen that occurs every four perforations to help locate position of frame line, especially in low-light level scenes. To use: Locate frame line. Determine whether it is offset from index marker by 0, +1, +2, or +3 perforations. Use this offset to find frame line elsewhere in scene. Note: The frame-index marker is not printed when it interferes with any other edgeprint information.
Frame rate: See "FPS."
Front End: General terms for all production and preparation work up to the Answer Print stage before Release Printing.
Gamma: Measurement of the contrast of an image, representing the slope of the straight-line portion of the characteristic curve.
Gate: The aperture assembly at which the film is exposed in a camera, printer, or projector.
Gelatin Filter (Gel): A light filter consisting of a gelatin sheet in which light-absorbing pigment or dye is incorporated.
Gobo: A patterned template used in lighting to create a pattern or texture in a scene. Placed between the light and the subject, a gobo can add mood, dimension, or the illusion of motion.
Grain Reduction: Digital algorithms used to reduce the amount of undesirable grain in a sequence of images.
Graininess: The character of a photographic image when, under normal viewing conditions, it appears to be made up of distinguishable particles, or grains. This is due to the grouping together, or "clumping" of the individual silver grains, which are by themselves far too small to be perceived under normal viewing conditions.
Granularity: Nonuniformity in a photographic image that can be measured with a microdensitometer.
Gray Card: A commercially prepared card that reflects 18 percent of the light hitting it. Visually it appears neutral, or a middle gray halfway between black and white.
Grayscale: A black and white image.
Gross Fog: The density of the base of the film plus the density of the fog in the emulsion. Also known as D-min and base + fog.
Guillotine Splicer: Device used for butt-splicing film with splicing tape.