CHROMAKEY–An electronic special effect that
combines two video sources into a composite
picture, creating the illusion that the two sources are
physically together.
CIRCLE OF ILLUMINATION–The total image area
of a lens, only part of which is actually used in taking
a picture.
CLOSE-UP –A photograph or a motion-picture scene
taken at a very close range that shows intimate detail
and captures and holds audience interest.
COATING, LENS–A thin, transparent coating applied
to the surface of lenses or other optical parts to
reduce reflection.
COINCIDENCE–Agreeing as to position. In a coinci-
dence type of range finder, when the two half
images of a distant object are in exact juxtaposition,
they are said to be “in coincidence."
COLLIMATED –A beam of light is said to be colli-
mated when all of its rays have been made parallel.
See SPECULAR.
COLOR BALANCE–The relationship between the
three images composing a color negative or positive
that provides an accurate (or, more generally, the
most pleasing) reproduction of natural colors. (PIA)
COLOR BARS–A color standard used by the television
industry for the alignment of cameras and videotape
recordings.
COLOR CHART–Target for test photography
composed of pigmented areas having colors of high
saturation, often accompanied by gray scales, and
useful in both color photography and in
black-and-white reproduction of colored objects.
An assembly of chromatic samples illustrating a
scheme of color classification. (PIA)
COLOR COMPENSATING FILTER–A filter used to
change the overall color balance of photographic
results obtained with color film and to compensate
for deficiencies in the quality of the light when
printing color films.
COLOR TEMPERATURE–The temperature to which
a black body radiator must be raised in order that
the light it emits may match a given light source in
color; usually expressed in degrees Kelvin (°K).
COLOR TEMPERATURE METER–An instrument
for estimating the spectral quality of a light source
or the illumination on a scene and expressing the
value in terms of color temperature. (PIA)
COLOR TRANSPARENCY–A positive image in
natural colors on a transparent support intended for
projection or for viewing by transmitted light. (PIA)
COLORBLIND –Applied to photographic layers
having only natural silver halide sensitivity to blue,
violet, and ultraviolet rays. (PIA)
COMA–An aberration of a lens that causes oblique
pencils of light rays from an object point to be
imaged as a comet-shaped blur.
COMPONENT–The processing of RGB (red, green,
and blue) channels as three separate channels.
COMPOSITE SIGNAL (Y/C)–(Also called NTSC
signal.) The video signal in which luminance “Y”
(black and white) and chrominance (red, green, and
blue) and sync information are encoded into a single
signal.
CONJUGATE DISTANCE–The distances of object
and image from the lens are called conjugate
distances. For every position that an object may
occupy with respect to a lens, there is a
corresponding position for the image.
CONTACT PRINT–Print produced by exposure in
immediate contact with the original or negative.
These prints are the same size as the original or
negative.
CONTAMINATION –Foreign matter in a processing
solution which impairs its operation.
CONTINUOUS TONE–Photographs in which the
detail and tone values of the subject are reproduced
by an infinite gradation of gray densities between
white and black. (PIA)
CONTRAST, LOW–A term expressing a relationship
of image tones in which highlights and shadows are
represented by very little difference in densities.
CONTRASTY–Photographic term applied to images
showing accentuated highlights and shadows. (PIA)
CONTROL TRACK–The area of the videotape used
for recording the synchronization information (sync
spikes).
COPY–(l) Any document or photograph to be
reproduced. (2) The results of such reproduction.
(3) (Verb) The act of reproducing a document.
COPYBOARD –The board, frame, or other device for
holding copy to be photographed.
CORROSION–The erosion of metals, as by the action
of an acid or an alkali; rusting; oxidation. (PIA)
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