PHOTOGRAPHY GLOSSARY (A-B)
Glossary - A
denotes the degree of refraction
of light of different wavelengths to different extents, given by
a transparent material, such as glass. The lower the Abbe number,
the greater the dispersion of colors.
Aberration - the inability of
a lens to produce a perfect, sharp image, especially towards the
edge of the lens field. These faults can be reduced by compound
lens constructions, and the use of small apertures.
Abrasion marks - marks on the emulsion surface of
a film, caused by scratching. It can be due to traces of dirt
trapped between layers of film as it is wound on the spool, or
to grit on the pressure plate.
Absolute released images - any images for which
signed model or property releases are on file and immediately
Absolute temperature - the temperature at which
most molecular movement ceases. It is often referred to as absolute
zero (-273° C).
Absorption - the process by which light falling
on a surface is partially absorbed by the surface.
Abstract - subjective, non-realistic image. An abstraction
photograph generally contains a design of patterns or shapes where
the identity of a subject is not evident.
Accelerator - chemical added to a developing solution
to speed up the slow working action of the reducing agents in
Acceptable Circle of Confusion - the size of the
largest circle which the eye cannot distinguish from a dot. In
35mm format cameras, a 0.03mm diameter circle of confusion is
considered acceptable. It is used to calculate depth-of-field
or depth of focus.
Acceptance angle - see Angle
Accessory shoe - metal or plastic fitting on the
top of the camera which supports accessories such as viewfinder,
rangefinder, or flash gun.
Acetate base - non-inflammable base support for
film emulsions which replaced the highly inflammable cellulose
Acetic acid - chemical used for stop baths and to
acidify acid fixing solution.
Acetone - solvent chemical used in certain processing
solutions that contain materials not normally soluble in water.
Achromatic - lens system that has been corrected
for chromatic aberration.
Acid - chemical substance with a pH
value below 7.
Acid fixing solutions - solutions which contain
an acid to neutralize any carry-over of alkaline developer on
the negative or print.
Acid hardener - substance used in acid fixer to
help harden the gelatin of the emulsion.
Acid rinse - weak acid solution used after development
and before fixation. By neutralizing alkaline developer left on
the photographic material it arrests development.
Actinic - the ability of light to cause a chemical
or physical change in a substance.
Actinometer - early type of exposure calculator.
Acuity - subjective term for the visual sharpness
of an image.
Acutance - objective measurement of image sharpness.
Adapter ring - circular mount, available in several
sizes, enabling accessories such as filters to be used with lenses
of different diameters.
Additive color - see Additive
Additive printing - color printing
method which produces an image by giving three separate exposures,
each filtered to one of the three primary color wavelengths, blue,
green and red.
Additive synthesis - method of producing full-color
images by mixing light of the three primary color wavelengths,
blue, green and red.
Aerial perspective - the distance
or depth effect caused by atmospheric haze. Haze creates a large
amount of extraneous ultra-violet light to which all photographic
emulsions are sensitive.
AF lock - stops autofocus operation once
the subject is in focus. Useful when shooting a subject outside
the focus area in the viewfinder. The photographer should first
lock the focus with the subject inside the focus area, then recompose
the shot as neccesary.
Afocal lens - lens attachment that alters the focal
length of the camera lens without disturbing the distance between
the lens and the film plane.
AF Sensor - the sensor used to detect focus.
Aftertreatment - the treatment of negatives and
prints to correct certain faults in exposure and development,
or to create special effects.
Agitation - method by which fresh solution is brought
into contact with the surface of sensitive materials during photographic
Air bells - bubbles of air clinging to the emulsion
surface during processing.
Air brushing - method of retouching b&w or color
photographs where dye is sprayed, under pressure, on to selected
areas of the negative or print.
Air-to-air photography - photography of aircraft
in flight from another aircraft.
Albert effect - effect that creates a reversed image.
An exposed frame of film, treated with dilute chromic acid is
exposed to light. Development then gives a positive image by darkening
the film grains that were not initially affected by exposure.
Albumen paper - printing paper invented by Blanquart-Evrard
in the mid-19th century where egg whites were used to coat the
paper base prior to sensitization. The albumen added to the brightness
of the white base and substantially improved printed highlights.
Alcohol thermometer - instrument used for measuring
temperature. It is an inexpensive and less accurate version of
the mercury thermometer.
Alkalinity - denotes the degree of alkali in a solution,
measured in pH
values. All values above pH 7 are alkaline.
Allegory - work of art that treats one subject in
the guise of another. An allegoric photograph usually illustrates
a subject that embodies a moral "inner meaning".
Alum - chemical used in acid hardening fixing baths.
Aluminum compounds - groups of chemicals often used
as hardeners in fixing baths.
Ambient light - the available light surrounding
a subject. Light already existing in an indoor or outdoor setting
that is not caused by any illumination supplied by the photographer.
Ambrotype - Mid-19th century photographic
process introduced in 1851-52 by Frederick Scott Archer and Peter
Fry. It used weak collodion
negatives which were bleached and backed by a black background
which produced the effect of a positive image.
Amidol - soluble reducing agent which works at low
Ammonium chloride - chemical used in toners and
Ammonium persulfate - chemical used in super-proportional
Ammonium sulfide - pungent but essential chemical
in sulfide or sepia toning.
Ammonium thiosulfate - highly active fixing agent
used in rapid fixing solutions which works by converting unused
silver halides to soluble complexes.
Amphitype - Mid-19th Century process based on an
underexposed albumen-on-glass negative. This was viewed by reflected
light against a black background to give a positive image similar
to a ambrotype.
Anaglyph - result of forming stereoscopic
pairs from two positives each dyed a different color, usually
green or red.
Analyzer - chart, grid or electronic instrument
used to determine correct color filtration when making color prints.
Anamorphic lens - lens capable of compressing a
wide angle of view into a standard frame.
Anastigmat - compound lens which has been corrected
for the lens aberration "astigmatism".
Angle of incidence - when light strikes a surface
it forms an angle with an imaginary line known as the :normal,"
which is perpendicular to the surface. The angle created between
the incident ray and the normal is referred to as the angle of
Angle of view - is the maximum
angle of acceptance of a lens which is capable of producing an
image of usable quality on the film.
Angstrom - unit of measurement
used to indicate specific points of wavelengths
within the electromagnetic spectrum. Visible light rays occur
between 4000 - 7000 Å.
Angular field - the angle subtended at the lens
by the diameter of the largest circle within which the lens gives
an image of acceptable sharpness and even illumination.
Anhydrous - dehydrated form of chemical. More concentrated,
so that less weight is needed in a formula than the crystalline
ANSI - speed rating system for photographic materials
devised by the American National Standards Institute.
Anti-fogging agent - constituent of a developer
that inhibits or reduces fogging during development.
Antihalation backing - dye used on the back of most
films capable of absorbing light which passes straight through
the emulsion. In this way it reduces the amount of extraneous
light that can be reflected from the camera back through the emulsion.
Antinous release - alternate term for a camera cable
Antiscreen plates - photographic plates containing
dyes that reduce the blue sensitivity. Used unfiltered, they can
give results similar to those obtained with yellow filtered orthochromatic
A-PEN - annealed polyethylene naphthalate. A polyester
material used as the base on Advanced Photo System film.
Aperture - circular hole in the
front of the camera lens which controls the amount of light allowed
to pass on to the film.
Aperture priority camera - semi-automatic camera
on which the photographer sets the aperture and the camera automatically
sets the shutter speed.
Aperture ring - ring located on the outside of the
lens usually behind the focusing ring, which is linked mechanically
to the diaphragm to control the size of the aperture.
Aplanat - lens which has been corrected for spherical
Apochromat - lens corrected for chromatic aberration
in all three primary colors.
APO (Apochromatic) - the ability to bring all colors
of the visible spectrum to a common plane of focus, within close
tolerances. It usually refers to a lens with such superior color
Apodization - lens treatment designed to cut down
diffraction fringes that appear around the images bright points
APS (Advanced Photo System) - consumer photography
developed by Kodak and four other companies - Canon, Fuji, Minolta
and Nikon . It is based on a new film format and photofinishing
Aquatint - etching technique
allowing control of tonal areas to produce almost unlimited gradations
from pale gray to black. Because of this it has also been used
in photography as an alternative term for gum
Archival permanence treatments - various treatments
given to prints to make them fade-resistant.
Arc lamp - photographic lamp in
which light is produced by passing an electric current through
two carbon rods.
Argentotype - Mid-19th century silver print process,
on which the kallitype
and sepia paper processes are based.
Aristotype - early commercial print type made on
collodion-chloride or gelatin-chloride paper.
Artificial daylight - artificial light having a
similar color temperature to daylight.
Artificial light - all light not originating from
a natural source - normally the sun.
Artificial light film - color film balanced for
use ion tungsten Artificial light, usually 3200 K.
ASA - original system of rating
photographic materials, which was devised by the American standards
Association. The ISO
rating system is now used in place of the ASA.
Aspect ratio - ratio of width to height in photographic
prints. The ratio is 2:3 in 35 mm pictures which produces photographs
most commonly measuring 3.5 x 5 inches or 4 x 6 inches.
Aspherical lens - lens with a curved, non-spherical
surface. Used to reduce aberrations and enable a more compact
Aspherical surface - lens surface with more than
one radius of curvature, i.e. the surface does not form part of
Assembly printing - method of printing using image
separations. Yellow, magenta, and cyan films are stacked to make
a final, full color print.
Assignment - definite OK to take photos for a specific
client with mutual understanding as to the provisions and terms
Astigmatism - lens aberration making a single point
light source impossible to focus as a true point.
ATA - term used to describe a camera, which supports
the electrical interface standard, defined by the PC Card Association
(formerly PCMCIA), known as ATA (AT Attachment). This is the mobile
computing equivalent of the IDE standard for desktop computers.
Atmospheric perspective - alternative term for aerial
Audiovisual - materials such as
filmstrips, motion pictures and overhead transparencies which
use audio backup for visual material.
Autochrome - early commercial color photography
process in which the principles of additive color synthesis were
Autofocus - device used in certain cameras, projectors
and enlargers that focuses the image automatically.
Automatic aperture - lens aperture
mechanism that stops down to s preset size just as the shutter
is fired, afterwards returning to the maximum aperture again for
focusing and composing the next image.
Automatic exposure control - system of exposure
setting in a camera, in which the electric current produced or
inhibited by the action of light on a photoelectric cell operates
a mechanism that adjusts the aperture and/or the shutter speed
Automatic iris - lens diaphragm which is controlled
by a mechanism in the camera body coupled to the shutter release.
Automatic lens - lens which remains at full aperture
whatever working aperture is set, until the shutter is released.
This allows optimum focusing, without affecting metering. Also
referred to as Automatic aperture.
Autowinder - film wind-on mechanism which moves
the film on one frame each time the shutter is released.
AV - see Audiovisual.
Available light - term applying to light normally
occurring in a scene, not supplemented by illumination intended
specifically for photography.
Axis lighting - light pointed at the subject from
a position close to the lens.
Azo dyes - compounds forming colors of great strength
and purity. Used in camera filters and integral tripack dye-bleach
Glossary - B
- letter on the
shutter dial indicating that the shutter will stay open while the
release is depressed.
Back focus - distance between the back surface of
the lens and the image
plane, when the lens is focused at infinity.
Background - area shown behind the main subject
in a picture.
Background density - density of any selection of
a negative or print on which there is no image. Also referred
to as Fog
Backing - dark coating, normally on the back of
a film, but sometimes between emulsion and base, to reduce halation.
The backing dye disappears during processing.
Back-lighting - light coming from behind the subject.
Back printing - information printed on the back
of a picture by the photofinisher. The system standard requires
the printing of frame number, film cassette number and processing
date automatically on the back of each Advanced Photo System print.
Back projection - projection system often used to
create location backgrounds in the studio.
Bag bellows - short flexible sleeve used on large
format cameras in place of normal bellows when short focal length
lenses are employed.
Balance - placement of colors, light and dark masses,
or large and small objects in a picture to create harmony and
Ball and socket - swiveling mount used to attach
a camera to a tripod, consisting of a large ball joint designed
to move in a cup.
Ballistic photography - photography of weapons,
ammunition and projectiles usually used for analysis.
Barium sulfate - compound
used in the manufacture of photographic printing paper to give
bright white highlights in the final print.
Barn doors - accessory used on spotlights and flood
lamps to control the direction of light and width of the beam.
Barrel distortion - one
of the common lens aberrations, where straight lines at the edge
of the field are caused to bend into the shape of a barrel.
Baryta - coating of barium
sulfate applied as the foundation to fiber based printing
Base - support for photographic emulsions. Available
in a choice of materials, including paper, cellulose, triacetate,
glass and estar.
Baseboard camera - portable large format camera
with a folding base-board. Allows a limited use of camera movements.
Also referred to as a field camera.
Base Exposure Time - initial exposure time used
for making a "straight" print.
Base-relief - photographic image effect usually
produced by printing from a negative and a positive sandwiched
together in the enlarger, slightly out of register.
Batch numbers - set of numbers printed on packages
of sensitive materials to indicate common production coating.
Beam splitter - mirror and prism system capable
of partly reflecting, partly transmitting light.
Belitski's reducer - solution used as a chemical
reducer for negatives. It consists of ferric potassium citrate
or oxalate in an acid fixing solution.
Bellows - light tight, folding sleeve which can
be fitted between the lens and the film plane.
Bellows shutter - obsolete shutter consisting of
a pair of bellows that, when closed together, form a hemisphere
enclosing the lens.
Between the lens shutter
- shutter usually placed within the components of a compound lens
close to the diaphragm.
Bichromate - refers to potassium bichromate or potassium
dichromate, used for bleaching and as a sensitizer for gelatin.
Bi-concave lens - simple
lens or lens shape within a compound
lens, whose surfaces curve toward the optical center. Such
a lens causes light rays to diverge.
Bi-convex lens - simple lens shape whose surfaces
curve outward, away from the optical center. Such a lens causes
light rays to converge.
Binocular vision - visual ability to determine three
photography depends on the use of binocular vision.
Bi-pack - combination of two films, differently
sensitized, but exposed as one.
Bi-refringence - splitting of light passing through
certain kinds of crystals into two rays at polarized right angles
to each other.
Bispheric lens - lens having different curvatures
at the center and the edge, each of which forms part of a sphere.
The different edge curvature brings the peripheral rays more closely
to the same point of focus as the center rays.
Bitumen - hydro-carbon which hardens by the action
of light. It was used by Joseph Nicephore Niepce to produce the
worlds first photograph in the early 19th century.
Black silver - finely divided metallic silver formed
from silver halides by exposure and development.
Bleach - chemical bath capable of rehalogenizing
black metallic silver.
Bleaching - stage in most toning, reducing and color
Bleach-out - method of producing line drawings from
photographic images. The photographic is processed in the normal
way, its outlines sketched, and the black metallic silver image
is then bleached away to leave a drawn outline.
Bleed - term used to describe a picture with no
borders, which has been printed to the edge of the paper.
Blocked up - a portion of an overexposed and/or
overdeveloped negative so dense with silver halides that texture
and detail in the subject are unclear.
Blocking out - method of painting selected areas
of a negative with an opaque liquid on the non-emulsion side.
Since light is unable to penetrate these areas they appear white
on the final print.
Blotter - sheet or sheets of absorbent material
made expressly for photographic prints. Wet prints dry flat and
quickly when placed between blotters.
Blowup - enlargement; a print that is made larger
than the negative or slide.
Blue print - alternative term for cyanotype.
Blue sensitive - sensitive to blue light only. All
silver halides used in traditional black and white emulsions are
sensitive to blue light, but early photographic materials had
only this sensitivity.
Blur - unsharp image areas, created or caused by
subject or camera movement, or by selective or inaccurate focusing.
Boom - adjustable metal arm, attached to a firm
stand, on which lighting can be mounted. Some booms are also made
to support cameras.
Borax - mild alkali used in fine grain developing
solutions to speed up the action of the solution.
Border - edge of a photographic print - either left
white, or printed black.
Boric acid - compound used in certain fixers to
prolong shier hardening life.
Bounce light - light that is directed away from
the subject toward a reflective surface.
Box camera - simplest type of camera manufactured,
and first introduced by George Eastman in 1888. It consists of
a simple, single element lens, a light tight box and a place for
film in the back.
Bracketing - technique of shooting a number of pictures
of the same subject and viewpoint at different levels of exposure.
Brightfield - method of illumination used in photomicrography
which will show a specimen against a white or light background.
Brightline viewfinder - viewfinder in which the
subject is outlined by a bright frame, apparently suspended in
space. This may show parallax correction marks, or lines indicating
the fields of view of different focal lengths.
Brightness range - subjective term describing the
difference in illumination between the darkest and lightest areas
of the subject.
Brilliance - intensity of light reflected from a
surface. It is sometimes an alternative term for luminosity.
Broad lighting - portrait lighting in which the
main light source illuminates the side of the face closes to the
Brometching - obsolete, special method of producing
a bromide print. The result acquired the texture of its support
and appeared similar to an etching.
Bromide paper - most common type of photographic
printing paper. It is coated with an emulsion of silver bromide
to reproduce black & white images.
Bromoil process - old printing process invented
in 1907, consisting of three stages. First, an enlargement is
made on bromide paper and processed. Second, the silver image
is removed in a bleacher which also modifies the gelatin so it
will accept lithographic ink. Third, while still damp the gelatin
is inked up by hand to create the image.
Brownie - trade name given to early Kodak box cameras.
Brush development - method of development in which
developer is applied to the material with a brush or similar instrument.
BSI - abbreviation for British Standards Institute.
Bubble chamber photography - method of analyzing
the paths of high-speed sub-atomic particles.
Buffer - chemical substance used to maintain the
alkalinity of a developing solution, particularly in the presence
of bromine which is produced during development.
Built-in meter - reflective light meter built directly
into the camera so that exposures can be easily made for the cameras
Bulb - See B.
Bulk film - film purchased in long lengths. Used
in a bulk camera back or with a bulk film loader.
Burning in - see Printing-in.
Butterfly lighting - lighting in which the main
source of light is -placed high and directly in front of the subject.