Glossary of Photography Terms

00000128358ca7aef3a87d82007f000000000001.Randall%27s%20Best%20Friend%20Known%20To%20Man Glossary of Photography TermsA glossary of photography terms used in photography, accompanied by definitions. In a number of cases, more in-depth information on the term can be found by surfing the Internet for definitions. I will update the Glossary of Photography Terms over time and as new terms become introduced. thephotographer4you objective is to present our viewers with the most comprehensive and thorough list of photography terms and definitions on the Internet.

Last Update: 4/25/10

Bandit

Photo: Delores Randalll


A

aberration An optical defect in a lens causing it to forman image that is not sharp or that is distorted. astigmatism, barrel distortion, chromatic aberration, coma, field curvature, pincushion distortion, spherical aberration.

acid A substance with a pH below 7. Since an acid neutralizes an alkali, a stop bath is usually an acidic solution that stops the action of the alkaline developer.

addictive color A way to produce colors of light by mixing light of the three  additive primary colors-red-green and blue.

automatic exposure A mode of camera operation in which the camera adjusts the shutter speed, the aperture, or both to produce the correct exposure. Abbreviated AE.

automatic flash An electronic flash unit with a light sensitive cell and electronic circuity that measures the light reflected back from the subject and terminates the flash when the exposure is correct.

agitate To move a solution over the surface of film or paper during the development so that fresh liquid comes into contact with the surface.

albuman Egg white; used in early photographic emulsions as a coating for glass plates and, more commonly, for printing paper.

alkali A substance with a pH balance above 7. Developers are alkaline solutions.

ambient light and available are one and the same The light that already exists where a photograph is to be made, as opposed to light brought in by the photographer. Often implies a relatively dim light.

ambrotype A collodion wet plate process in which the emulsion was coated on a glass plate. The negative image produced was visible as a positive image when the glass was backed with a dark material.

angle of view The area seen by a lens or viewfinder or read by a light meter.

aperture The size of the lens opening through which light passes.

aperture priority A mode of automatic exposure in which the photographer selects the aperture and the camera sets the shutter speeds that will produce the correct exposure.

archival processing Processing designed to protect a print or negative as much as possible from premature deterioration caused by chemical reaction.

artificial light Light from an electronic lamp, a flash bulb, or electronic flash. Often describes light that the photographer has set up to illuminate a scene.

ASA A film speed rating similiar to an ISO rating.

astigmatism A lens aberration or defect that is caused by the inability of a simple lens to focus oblique rays uniformly.

automatic exposure A mode of camera operation in which the camera adjusts the shutter speed, the aperture, or both to produce the correct exposure, example AE.

automatic flash An electronic flash unit with a light sensitive cell and electronic circuity that measures the light reflected back from the subject and terminates the flash when the exposure is correct.

automatic focus A system by which the camera adjusts its lens to focus on a given area – the center of the image.

Av Averture value. Used on some camera information displays as a shortened way to refer to aperture settings (f-stops)

axis lighting Light pointed at the subject from a position close to the camera’s lens.

B

back lighting Light that comes from behind the subject toward the camera.

backup An exact duplicate of a digital file or a group of files, made as protection against loss or damage.

banding Visible tonal bands produced by converting a continuously varying gradation into too few discrete gray levels.

barrel distortion A lens aberration or defect that causes straight lines to bow outward, away from the center of the image.

bellows A flexible, light tight, and usually accordion folded part of a view camera between the lens board in front and the viewing screen in back. Also used on a smaller camera for closeups.

binary number A number consisting of one or more 1s and Os.

bit The smallest unit of information usable by a computer, indicated a 1 or a O, describing one of two conditions: on or off.

bit depth The number of bits used to represent each pixel in an image, determining its color and tonal range.

bleed mount To mount a print so that there is no border between the edges of the print and the edges of the mounting surface.

blocked up Describes highlight areas that lack normal texture and detail. Due to excess contrast overexposure or overdevelopment.

blooming Streaks or halos in a digital image around light sources or bright reflections. Caused by leaking of electrical charge between CCD elements due to overexposure.

blotters Sheets of absorbent paper made for photographic use. Wet prints can be dried by placing between blotters.

bounce light Light that does not travel directly from its source to the subject but is first reflected off another surface.

bracket To make several exposures, some greater and some less that the exposure that is calculated to be correct. Bracketing allows for error and permits selection of the best exposure after development.

brightness A subjective impression of the lightness of an object. The correct term for the measurable quantity of light reflected or produced by an object is luminance.

broad lightening Portrait lighting in which the main source of light illuminates the side of the face turned toward the camera.

built in meter A reflected light exposure meter built into a camera so that light readings can be made directly from camera position.

bulb A shutter setting marked B at which the shutter remains open as long as the shutter release is held down.

burn (or burn in) 1. To darken a specific area of a print by giving it additional printing exposure. 2. To darken an area of a digital image during image editing.

butterfly lighting Portrait lighting in which the main source of light is placed high and directly in front of the face.

byte A unit of digital data containing eight bits.

C

cable release A long coiled wire with a plunger at one end a socket at the other that attached to a camera’s shutter release. Pressing the plunger releases the shutter without touching and moving the camera.

calibrate To adjust the output of a digital device, such as a computer monitor, to match a predefined standard.

calotype The first successful negative/positive photographic process; it produced an image on paper. Invented by Talbot, called Talobyte.

camera A picture taking device usually consisting of a light tight box, a place for film or digital sensor, a shutter to admit a measured quantity of light, and a lens to focus the image.

camera obscura Latin for “dark chamber;” a darkened room with a small opening through which rays of light could enter and form an image of the scene outside. Eventually a lens was added at the opening to improve the image, and the room was shrunk to a small, portable box.

carte-de-visite A small portrait, the size of a visiting card, popular during the 1860′s. People often collect them in albums.

cassette/cartridge A light tight metal or plastic container that permits a roll of 35mm film to be loaded into a camera in the light.

catchlight A reflection of a light source in a subject’s eye.

CCD Charge-coupled device. One of two types of light sensing devices, the other is CMOS placed in a grid to make the sensor in the a digital camera. Also used as light sensing device in scanners.

changing bag A light tight bag into which a photographer can insert his or her hands to handle film when a darkroom is unavailable.

characteristic curve A diagram of the response to light of a photographic material, show how increasing exposure affects silver density during development. Also called the D log E curve, since density is plotted against the logarithm of the exposure.

chromatic abberration A lens defect that bends light rays of different colors at different angles and therefore focuses them on different places.

chromogenic film Film in which the final image is composed of dyes rather than silver.

circle of confusion The size of the largest circle, for a given image size and viewing distance, that can’t be distinguished from a point or dot. Affects depth of field by determining which parts of an image will appear to be in focus and which will not.

close up A larger than normal image that is formed on a negative by focusing the subject closer than normal to the lens with the use of supplementary lenses, extension tubes or bellows.

CMOS Complementary metal oxide semiconductor. One of two types of light sensing devices (the other is CCD) placed in a grid to make the sensor in a digital camera.

CMYK The four colors used in printing on a press or with most digital printers: cyan, magenta, yellow, and black. Digital images may be stored or edited as CMYK or RGB (red, green, blue) and converted between them.

collodian A transparent, syrupy solution of pyroxylin (a nitrocellulose) dissolved in ether and alcohol; used as the basis for the emulsion in the wet plate process.

color balance 1. A film’s or a sensor’s response to the colors of a scene. Color films are balanced for use with specific light sources. Also white balance. 2. The reproduction of colors in a color print, alterable during image editing or darkroom for color printing.

color cast A trace of one color in all the colors in an image.

color compensating filers Gelatin filters that can be used to adjust the color printing. More expensive than acetate color printing filers, they can be used below the enlarger lens if the enlarger has no other place for filters.

color management A means of coordinating the color output of various devices so that the colors you see in a digital image on your monitor, for example, will be the ones that appear when you print the image.

color temperature A numerical description of the color of light measured in degrees.

color temperature meter A device for estimating the color temperature of a light source. Usually determine the filtration needed to match the color balance of the light source with that of standard types of film.

coma A lens aberration or defect that causes rays that pass obliquely through the lens to be focused at different points on the film plane.

complementary colors 1. Any two colors of light that when combined include all the wavelengths of light and thus produce white light (see addictive color) 2. Any two dyes colors that when combined absorb all wavelengths of light and thus produce black (see subtractive color). A colored filter absorbs light of it complementary color and passes light of its own color.

compression A means of reducing the file size for a digital image in order to reduce storage requirements or transmission speed across networks. “Lossy” techniques permanently eliminates information to obtain highly compressed, very small files. Lossless techniques compress images without losing any original information in the file.

condenser enlarger An enlarger that illuminates the negative with light that has been concentrated and directed by condenser lenses placed between the light source and the negative.

contact printing The process of placing a negative in contact with sensitized material, usually paper, and then passing light through the negative onto the material. The resulting image is the same size as the negative.

contamination Traces of chemicals that aer present where they don’t belong, causing loss of chemical activity, staining, or other problems.

continuous tone Describes an image with a smooth gradation of tones from black through gray to white.

contrast The difference in darkness or density between one tone and another.

contrast filter A colored filter used on a camera lens to lighten or darken selected color in a black and white photograph. For example, a green filter used to darken red flowers against green leaves.

contrast grade The contrast that a printing paper produces. Systems of grading contrast are not uniform, but in general grades 0 and 1 have low or soft contrast; grades 2 and 3 have normal or medium contrast; grades 4,5, and 6 have high or hard contrast.

contrasty Describes a scene, negative, or print with very differences in brightness between light and dark areas. Opposite: flat.

convergence The phenomenon in which lines that are parallel in a subject, such as the vertical lines of a building, appears nonparallel in an image.

cool Bluish colors that by association with common objects (water, ice, and etc.) give an impression of coolness.

correction filter A colored filter used on a camera lens to make black and white film produce the same relative brightnesses percieved by the human eye. For example, a yellow filter used to darken a blue sky so it does not appear excessively light.

covering power The area of the focal plane over which a lens projects an image that is acceptably sharp and uniformly illuminated.

crop To trim edges of an image, often to improve the composition. Cropping can be done by moving the camera position while viewing a scene, by  adjusting the enlarger or easel during printing, by using a cropping tool during printing, by using a cropping tool during image editing, or by trimming the finished product.

curvilinear distortion see barrel distortion; pin cushion distortion.

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