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color generator • color spectrum 127
color generator A special radio-frequency (RF) signal
generator to adjust or troubleshoot a color
television receiver. The color signals it delivers
are identical to those produced by a broadcast
station.
color graphics Computer graphics displayed in
color on a cathode-ray tube (CRT) or liquidcrystal
display (LCD).
colorimeter A device used to quantitatively measure
the color intensity of a sample relative to a
standard.
colorimetric A characteristic of visible light, representing
the wavelength concentration. Refers to
the perceived color of a light beam.
colorimetry The science and art of color measurement.
color killer In a color television receiver, a circuit
that, in the absence of a color signal, delivers a
negative bias to cut off the bandpass amplifier.
color match In photometry, the condition in which
color agreement exists between the halves of an
area. Also see COLOR MATCHING.
color matching The art of selecting colors that are
identical in hue, saturation, and brilliance. This
can be done with the unaided eye or with the help
of an instrument.
color media Substances that transmit essentially
one color of visible light while blocking other colors.
color meter A photoelectric instrument for measuring
color values, and comparing and matching
colors.
color mixture An additive combination of two or
more colors. Thus, red + yellow = orange, blue +
red = violet, red + blue + green = white, etc.
color oscillator The oscillator in a color television
receiver that coordinates the color response. This
oscillator is operated at 3.579545 MHz, to within
plus or minus 10 Hz.
color palette In a color video image, the total number
of possible colors that can be displayed.
color phase In color television, the phase difference
between an I or Q chrominance primary signal
and the chrominance carrier reference.
color-phase diagram In color television, a quadrant
diagram showing (for each of the three primary
and complementary colors) the difference in
phase between the color-burst signal and the
chrominance signal, as well as the peak amplitude
of the chrominance signal. Also shown are
the peak amplitude and polarity of both in-phase
and quadrature components required for the
chrominance signals. For color TV receiver adjustment,
the color-phase diagram is displayed,
in effect, by a VECTORSCOPE when a suitable
signal from a color generator is applied to the receiver.
color picture signal 1. In color television and/or
computer graphics, an electrical signal containing
components corresponding to the hue, saturation,
and brilliance of a fixed or changing visual
image. 2. In color television, the combination of
chrominance and luminance signals minus
blanking and sync signals.
color picture tube A specialized type of cathoderay
tube (CRT), used in color television receivers
and computer displays. Three different images
are produced: one in red, one in blue, and one in
green. The three monochrome images are combined
to form a complete color image.
color primaries 1. Also called additive primaries or
primary colors. In color television, the hues red
(R), green (G), and blue (B). When these colors are
mixed in various ratios, any visual color can result.
2. Also called subtractive primaries or primary
pigments. In color printing, the hues
magenta (M), cyan (C), and yellow (Y). These
roughly correspond to red (R), blue (B) and yellow
(Y). Sometimes black (K) is also included. When
these pigments are mixed in various ratios, any
visual pigment can result.
color purity The ratio of wanted to unwanted components
in a color. In a pure color, there are no
components other than those required to produce
the color. Color, in this context, includes white,
black, and all shades of gray.
color-purity magnet A permanent magnet on the
neck of a color television picture tube, used to
help ensure color purity by maintaining proper
displacement of the electron beam.
color registration In color television reception, the
precise superimposition of red, green, and blue so
that the composite is free from COLOR EDGING.
color rendering index A mathematical expression
defining the effect of the color of a light source on
an object. For example, in red light, a blue object
appears nearly black.
color sampling rate The number of times per second
that each primary color is sampled in a color
television receiver.
color saturation A measure of the purity of a hue.
The extent to which a hue is without a white component;
100% saturation indicates a complete
absence of white.
color sensing In machine vision systems, the ability
to distinguish between light of different wavelengths.
Usually done with red, green and blue
color filters and three separate cameras.
color sensitivity 1. The degree of which a photosensitive
device, such as a photocell or camera
tube, responds to various colors of light. 2. The
degree to which photographic film responds to
various colors of light.
color signal See COLOR PICTURE SIGNAL.
color spectrum The band of electromagnetic energy
containing visible light; it extends from red
(at the longest wavelengths) to violet (at the shortest).
Commonly measured in nanometers (nm),
where 1 nm = 10 –9 m. Also expressed in
Angstroms, where 1 Angstrom = 10 –10 m = 0.1
nm. In order of decreasing wavelength, the colors
are red at 750 to 700 nm (7500 to 7000