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GLOSSARY
2D Two-dimensional, as in 2D graphics. Defining
a plane or lying on one.
3D Three-dimensional, as in 3D graphics. Defining
a solid or volume, or having the appearance of a
solid or volume.
24x speed The device reads or writes data at 24x
the basic rate for the device—for CDs and memory
cards, 150 KB per second. DVDs read and write at a
basic speed about 9x greater than CDs.
24-bit A measure of the size or resolution of data
that a computer, program, or component works
with. A color depth of 24 bits produces millions
of different colors.
35efl 35mm equivalent focal length. A digital
camera’s lens focal length expressed as the
equivalent focal length for the 35mm film format.
36-bit A measure of the size or resolution of data
that a computer, program, or component works
with. In imaging, it equates to allocating 12 bits
to each of the R, G, B (red, green, blue) channels.
A color depth of 36 bits gives billions of colors.
5,000 The white balance standard for pre-press
work. Corresponds to warm, white light.
6,500 The white balance standard corresponding
to normal daylight. It appears to be a warm white
compared with 9,300.
9,300 The white balance standard close to normal
daylight. It is used mainly for visual displays.
A
aberration In optics, a defect in the image
caused by a failure of a lens system to form a
perfect image.
aberration, chromatic An image defect that
shows up as colored fringes when a subject
is illuminated by white light, caused by the
dispersion of white light as it passes through
the glass lens elements.
absolute colorimetric A method of matching
color gamuts that tries to preserve color values as
close to the originals as possible.
absolute temperature A measure of
thermodynamic state, used to correlate to the
color of light. Measured in Kelvins.
absorption Partial loss of light during reflection
or transmission. Selective absorption of light causes
the phenomenon of color.
accelerator A device that speeds up a computer
by, for example, providing specialist processors
optimized for certain software operations.
accommodation An adjustment in vision to keep
objects at different distances sharply in focus.
achromatic color Color that is distinguished by
differences in lightness but is devoid of hue,
such as black, white, or grays.
ADC Analog-to-Digital Conversion. A process
of converting or representing a continuously varying
signal into a set of digital values or code.
additive A substance added to another, usually
to improve its reactivity or its keeping qualities,
especially in lengthening the life span of a print.
additive color synthesis Combining or blending
two or more colored lights in order to simulate
or give the sensation of another color.
address Reference or data that locates or identifies
the physical or virtual position of a physical or
virtual item: for example, memory in RAM; the
sector of hard disk on which data is stored; a dot
from an ink-jet printer.
addressable The property of a point in space that
allows it to be identified and referenced by some
device, such as an ink-jet printer.
algorithm A set of rules that defines the repeated
application of logical or mathematical operations
on an object: for example, compressing a file or
applying image filters.
alias A representation or “stand-in” for the
continuous original signal: it is the product of
sampling and measuring the signal to convert it
into a digital form.
alpha channel A normally unused portion of a file
format. It is designed so that changing the value of
the alpha channel changes the properties—
transparency, for example—of the rest of the file.
analog An effect, representation, or record that is
proportionate to some other physical
property or change.
antialiasing Smoothing away the stair-
stepping, or jagged edge, in an image or in
computer typesetting.
GLOSSARY

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