DCS: Desktop color separation. Used when
saving photographs as EPS files. It is simply a document format
used in Desktop Publishing.
Decrement: In color process printing, it
describes the decrease of a brightness, hue, or saturation value
in an image.
Densitometer: In lithography, a reflection
densitometer is used to measure the density of the ink colors to
determine they are consistent throughout the run. A transmission
densitometer can be used to check reproduction dot sizes in order
to maintain quality assurance in color. Both measure optical
density and are considerably more sensitive and accurate than is
the human eye.
Density: A measure of the relative difference
between a whit area and a toned or black area. Can be applied
both to black and white and color. Or the ability of a material
to absorb light. It is inversely proportional to the amount of
light reflected or transmitted through a sample.
Descenders: A typographic term for the
portion of lowercase characters that falls below the main body of
the letter. The lower case g, j, p, q and y have descenders.
Device Independent: A program or file format
that can be used with two or more different computing devices and
produce identical results. For example, a page saved in
Postscript format should be printable on an HP LaserPrinter IV or
on a Linotronic output device.
Differential Spacing: In typography, allowing
letters to take up varying horizontal space in relation to their
widths. For example, the "i" takes up less space than
an upper-case "W". Opposite of fixed spacing, where
each letter is assigned the same space regardless of its shape or
Digitize: To convert an image or signal into
binary code. Visual images are digitized by scanning them and
assigning a binary code to the resulting vector or raster
Display PostScript: The PostScript command
set that renders images directly to the screen.
Display Type: Used for headlines and
advertising copy, it is larger than 14 points.
Dithering: Simulating gray tones by altering
the size, arrangement or shape of background dots.
Dot: The individual element of a halftone.
Its size (density) can be related to the density of the original
used to produce the halftone dot. The size of the dot is
indicated by the percentage of the area it occupies from zero to
one hundred percent. It may be several shapes including round,
square or elliptical.
Dot Gain: An increase in the size of halftone
dots that may occur as a result of errors or imperfections in any
of the steps between screening an image and printing it onto
paper. Common causes of mechanical dot gain are incorrect plate
exposure, excessive tack or incorrect viscosity of printing ink,
excessive ink film thickness, internal reflection of the ink, or
too much pressure between the blanket roller and impression
Dot Spread: In printing, a defect in which
dots print larger than they should, causing darker tones or
colors. (See Dot Gain)
Double Burn: The merging of two films into
one using a contact screen camera. It is usually used to bring
the black text into the black separation.
DPI: Dots Per Inch. A measurement of output
device resolution and quality. Measures the number of dots a
printer can print per inch both horizontally and vertically. A
600 dpi printer can print 360,000 (600 by 600) dots on one square
inch of paper.
DSC: Document Structuring Convention. Also
known as ADSC (Adobe Document Structuring Conventions) Postscript
Format. Used as standards in the process of creating PostScript.
Dummy: A preliminary layout showing the
position of illustrations and text as they are to appear in the
final reproduction. A set of blank pages made up in advance to
show the size, shape, color form and general style of a piece of
printing. Also used to show imposition layout for stripping
Dynamic Range: A scanner's ability to capture
an image's gradations from the lightest highlight to the darkest