THIS IS A PHOTOGRAPHY DICTIONARY OR A GLOSSARY.
HERE YOU WILL FIND MEANINGS OF WORDS USED IN PHOTOGRAPHY.
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18 percent gray card — A card with a matte surface of 18 percent reflectance used as a standard tone for metering and printing purposes.
4/1 — A job printed with four colors of ink on both sides of the sheet. See process colors, subtractive color.
4/1 — A job printed with four colors of ink on one side of the sheet, and one color of ink on the other.
aa filter— most digital slr cameras employ a low pass or anti-aliasing filter in front of the sensor to help prevent aliasing.
aberrations — Image flaws or imperfections due to lens design, causing image distortion or degradation of image sharpness. See also astigmatism, barrel distortion, chromatic aberration, coma, compound lens, curvature of field, pincushion distortion, spherical aberration.
Absolute Colorimetric Rendering: One of the four ICC-specified rendering intents used for handling out-of-gamut colors in color matching. Absolute Colorimetric rendering is exactly the same as Relative Colorimetric Rendering, except that Absolute Colorimetric rendering compares the white point of the source color space to that of the destination color space and shifts all colors accordingly.
accelerator — A developer component, usually an alkali, that increases the speed of development.
acceptance angle — See angle of view.
acetic acid — An acid used in diluted form as a stop bath. Also found in vinegar.
achromat — A lens system designed to correct the effects of chromatic aberration so that the two different wavelengths of light have the same focal length.
achromatic — By definition, having no color, therefore, completely black, white or some shade of gray.
Achromatic Color — A neutral color (white, gray or black) that has no hue.
Additive Color Mixture — Mixing of the three primary color lights (red, green and blue) to obtain colors. For example, combining green and red creates yellow, red and blue creates magenta, and blue and green create cyan.
Additive Primary Colors: The primary colors of light, from which all other colors can be made -- red, green, and blue. Adding 100 percent of all three produces white light, while adding lesser intensities produces a gamut of different colors. Combining 100 percent of two additive primaries produces a subtractive primary: red+green=yellow red+blue=magenta green+blue=cyan
acid — A compound that neutralizes alkalis. Acids have a pH of less than 7.0.
actions — A recorded series of steps and commands that can be played back to automate repetitive processes. Actions are particularly useful for resizing a number of images, changing resolution, saving a folder full of images in a different file format, and many other common tasks that rely on a defined series of steps.
acutance — The ability of a film to produce a sharp edge between two tonal areas in the image, tested by placing a knife-edge on the film and exposing it to light. Acutance is an objective measure related to image sharpness.
ad converter — in-camera device that converts analogue information (the output of the camera sensor) into numbers that can be read by a computer. adapter rings — Metal rings used to adapt smaller or larger threaded filters or accessories to the threaded fitting on a camera lens. See also step-down ring, step-up ring. adaptive palette — A sampling of colors taken from an image and used in a special compression process, usually to prepare images for the World Wide Web. additive color — The process of mixing red, green and blue light to achieve a wide range of colors, as on a color television screen. See subtractive color. additive color system — A method of adding varying amounts of the additive primaries to achieve the desired color of light. additive primaries — See primary colors. adjacent color — An adjoining color. Since the eye responds to strong adjoining color, it’s perception of a particular color is affected by any nearby colors. This means that a color with adjacent colors may look different than it does in isolation. Advanced Photo System (APS) — A subminiature film and camera system that uses film in a selfcontained cartridge, and produces an image format size of 16x24mm. The negatives are returned to the cartridge after printing, so the film is never directly handled. AE — Automatic exposure. aerial image — A real optical image formed in space. To be visible, it must be projected onto a ground glass or screen, or inspected through another lens. aerial perspective — An indication of depth caused by the increasing effect of atmospheric disturbance or haze as distance increases. AF — Automatic Focus. agitation — Movement— such as stirring or inverting a container— that causes a processing solution to circulate over the surface of a photosensitive material, providing fresh solution to all area. air bells — Bubbles of air that cling to a photographic material during processing. Also refers to the spots resulting from less complete development of the material where air bubbles clung to it during developing. Pre-wetting film and vigorous agitation prevent air bubbles. Airbrush — A spray device that uses compressed air. Used to apply dyes or paints for retouching and protective coatings. albumen — The white of an egg. Used as a carrier for silver salts in 19th-century photographic prints and plates. algorithm — A specific sequence of mathematical steps to process data. A portion of a computer program that calculates a specific result. aliasing— information in the image that wasn’t in the original scene – usually appears as ‘jaggies’ (stair-stepping) or color fringing. alignment — Positioning content to the left, right, center, top, or bottom. alkali — A compound that neutralizes acids and has a pH greater than 7.0 Also called a base. alpha channel — An additional channel in a image that defines what parts of the image are transparent or semitransparent. Programs such as Adobe Illustrator, Photoshop, Premiere, and After Effects use alpha channels to specify transparent regions in an image. 3 of 85 ambience — The light-reflecting nature of the subject environment. An environment with many lighttoned, reflective surfaces has a high ambience. One with dark, light-absorbing surfaces has a low ambience. The amount of environmental light is influenced by the ambience. ambient light — See available light, continuous light, environmental light, preexisting light. This term is not used in this book because of inconsistent usage. ambient temperature — The temperature of an environment. For photographic processes, this is usually room temperature. ambrotype — A slightly underexposed collodion wet-plate glass negative displayed in a frame backed by black material. When viewed at the correct angle to a light source, it appears positive. Popular during the nineteenth century. American National Standards Institute (ANSI) — An organization that develops and publishes standard methods for measurement and procedures in several fields, including photographic technology. American Standards Association (ASA) — Former name of American National Standards Institute. amount of development — The total amount of chemical reduction of silver salts to silver during development, which is affected by the development time, development temperature, amount of agitation during development, type of developer, and condition of the developer. analog image — A photographic image in which the tones of the original subject are represented by a continuously variable substance. For example, in a black-and-white photographic print, the tones of the subject are represented by varying amounts of silver. In an analog video image, the subject tones are represented by voltage that produces varying magnetic patterns on video tape. As opposed to a digital image. analog readout — A data display for a meter or other device that is in the form of a pointer, such as a needle, moving along a scale. analogous colors — Colors related to each other by their proximity in wavelength. For example, red, orange, and yellow are analogous colors, as are blue, green, and violet. analogue— continuously variable. anastigmat — A lens system designed to correct the effects of astigmatism. angle of acceptance — See angle of view. angle of coverage — The angle between the lines from a lens to the ends of a diameter of the circle of usable image the lens can form on the film. The angle of coverage determines how large a format the lens can cover. angle of incidence — The angle between a ray of light striking a surface and a line perpendicular to the surface at the point where the ray meets the surface. angle of reflection — The angle between a reflected ray of light and a line perpendicular to the surface where the ray met the surface. See also law of reflection. angle of refraction — The angle between a refracted ray of light and a line perpendicular to the surface where the ray passed through the surface. angle of view — 1) For a camera lens, the angle between the lines from the lens to the ends of the diagonal of a rectangle outlining the area of the subject included on the negative, determined by the focal length of the lens and the size of the film format. 2) For a reflected-light meter, the angle between the lines from the meter receptor to the ends of the diagonal of the rectangle or the diameter of the circle outlining the area of the subject included in the meter reading. Also called angle of acceptance or field coverage. 4 of 85 animated GIF — A type of sequential file format where multiple bitmap images are displayed one after another. animated graphics — Images of any type that move. animation — The technique of simulating movement by creating slight changes to an object or objects over time. ANSI — See American National Standards Institute. anti-aliasing — A graphics software feature that eliminates or softens the jaggedness of low-resolution curved edges. anti-aliasing— the process of reducing stair-stepping by smoothing edges or removing high frequency information. anti-halation backing — A film backing containing absorbing dyes, intended to reduce halation. antistatic — A brush, cloth, or gun that is used to neutralize static charge on the surface of film or other material, making it easier to remove dust, lint, and other particles.
aperture — An opening, usually variable in size, located in or near a lens, that is used to control the amount of light that reaches the photosensitive material. See also relative aperture.
aperture priority — An automatic in-camera metering system in which the aperture is set manually and the meter sets the shutter speed automatically. See also shutter priority.
apochromat — A lens designed to correct for the effect of chromatic aberration so that three different wavelengths have the same focal length (compare with achromat). Often used to describe highly corrected lenses of excellent image quality. application — See program. application's menus. For example, .scanner software may be supplied as a plug-in so the scanner operation can he accessed from within an application. APS — See Advanced Photo System. archival — Photographic prints described as archival are produced using materials and processing techniques intended to provide maximum image permanence. Also describes storage and handling techniques intended to provide maximum image permanence. archiving — The process of storing data in a secure and safe manner. Archived data, recorded on tape or optical media, is typically stored offsite to prevent total data loss in case of a catastrophic event. See backing up. art — Illustrations and photographs in general. All matter other than text that appears in a mechanical. artifact — A visible defect in a digital image, produced by the electronic imaging process. artifact — Something that is artificial or not meant to be there. An artifact can be a blemish or dust spot on a piece of film, or unsightly pixels in a digital image. artifact(ing) — the introduction of erroneous information (errors) in an image, usually caused by the jpeg compression system. artificial light — Illumination from manufactured sources including light bulbs, electronic flash, flashbulbs, and other light sources powered by electricity. ASA — American Standards Association. Also an exposure index system devised by that organization. 5 of 85 ascender — Parts of a lowercase letter that exceed the height of the letter “x”. The letters b, d, f, h, k, and t have ascenders. ASCII — American Standard Code for Information Interchange. Worldwide, standard ASCII text does not include formatting, and therefore can be exchanged and read by most computer systems. aspect ratio — The ratio of width to length of a negative or print. A square image has an aspect ratio of 1. An 8 X 10-inch print has an aspect ratio of 0.8. aspect ratio — The width-to-height proportions of an image. aspheric — Describes a lens with one or more nonspherical surfaces. asset — An image, sound, video, or other file that may be in use in a Web page. assignment photography — Specific photographic jobs performed at the request of and under the direction of a client, usually on a freelance or contract basis. assistant — A person in the photographic industry who assists a photographer in a studio or on location, working under the direction of the photographer, either on a freelance basis or as a permanent employee. association — Connecting emotions or ideas with visual elements in a photographic image. Also refers to the connection of objects not represented in the photograph to shapes in the photograph by their similarity in appearance (as in seeing the shapes of animals in clouds). astigmatism — A lens aberration that causes off-axis points to be imaged as two perpendicular lines in different planes. See also anastigmat. asymmetrical balance — A visual balance in the design of a photograph that is achieved not by symmetry but by balancing the visual weights of the various design elements, taking into account all the factors that affect their visual importance. asymmetrical power pack — A power pack for a studio electronic flash that has two or more banks of unequal power, allowing different amounts of power to be supplied to different heads. audience — Viewers of a movie, videotape, or commercial. auto white balance — Feature on most cameras to achieve white balance with no user intervention. automatic diaphragm — A diaphragm aperture that remains open to its maximum aperture, regardless of the f/stop setting, until the shutter is released. When the shutter is released, it stops down to the set aperture before the shutter opens and reopens to its widest aperture after the shutter closes. Used in single-lens reflex cameras to provide a bright viewing screen. automatic exposure (AE) — An in-camera metering system in which the shutter speed, aperture, or both are ser automatically by the meter. See also aperture priority, program operation, shutter priority. automatic flash — An electronic flash containing a metering device that measures flash light reflected from the subject and cuts off the flash when sufficient exposure has been achieved. automatic focus (AF) — A camera system that automatically focuses the lens on the subject matter that appears within a specific area of the viewfinder. Also called autofocus. available light — Preexisting light. This term is used most often to refer to preexisting light at a low level of illumination. averaging meter — A reflected-light meter with an angle of view of 30-45°- When used from the camera position, it covers about the same subject area as a camera equipped with a normal lens. axial — In optics, describes image points on the axis or light rays that enter a lens along its axis. 6 of 85 axis — In optics, a line drawn through the centers of curvature of the lens surfaces. axis lighting — Lighting a subject with a lamp or flash placed as close as possible co the camera lens. Also called level front lighting.
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