Contex SD3600 - Page 64

C-4
Appendix - C --- Scanner Terms
Device Prole
A le used as part of a Color Management System
(CMS). A device prole contains information about
the characteristics of a scanner, computer display
or printer. The format for device proles (Win95,
Colorsync. etc.) is standardized by ICC (Interna-
tional Color Consortium).
DIP
Digital Image Processor. Hardware embedded
function that does image enhancement in real-time
while scanning.
Dither
To use patterns of different colored pixels to create
blended colors; or, to use dots of different sizes to
simulate grayscale images. (see below)
Dithering
A printing or display device may have only a small
number of grayscale or color values for each de-
vice pixel. However, if the viewer is sufciently dis-
tant from the printed page or display, the value of
neighboring pixels can be set so that the viewer’s
eye integrates several pixels to achieve an appar-
ent improvement in the number of levels or colors
that can be reproduced.
Dots Per Inch (dpi)
A measure of dots in a square inch where the indi-
vidual element is a round dot on the printed page.
DPI
Dots Per Inch, equivalent to Pixels Per Inch. An
expression of resolution of a scanned image.
DSP
Digital Signal Processor, does image enhancement
in real-time while scanning.
Dual 2D-Adaptive Enhancement
Enhancement processing on the foreground and
background separately. Processing is performed
on-the-y. The separate enhancement processes
are simultaneously performed on different drawing
aspects.
Dynamic Range
A measurement of scanner quality; the density dif-
ference between highlights and shadows.
Edit
Modify an entry using standard Windows text-edit-
ing techniques.
Emulsion
The light sensitive silver, coated on the clear ac-
etate lm base, that forms the photograph when a
picture is taken and the lm is developed.
Equalizing
Distributing all color or tone equally along a density
range.
File Format (image)
The format in which a scanned picture is saved.
Many programs can insert or import a picture
from a le, if it is saved in a le format that the
program supports. Common le formats include
TIFF (Tagged Image File Format), BMP (Windows
bitmap), JPEG (Joint Photograph Expert Group),
and FPX (FlashPix format).
Flip Horizontal
To ip the picture left/right.
Foreground
Foreground when scanning raster data (black and
white, or monochrome data) refers to the pixels
that represent data of interest (background refers
to everything else). Typically, lines and shapes
are represented by black pixels (foreground) and
empty space is represented by white pixels (back-
ground). When scanning grayscale data, back-
ground means the gray level of a region of pixels
that surrounds some desired foreground data.
Gamma Adjustment
An adjustment that makes the tone distribution
lighter or darker in an image.
Gamut Transformation
Color Management System function, where out-
of-gamut colors are converted to colors within the
gamut of the targeted device, e.g., a printer.
Gamut
The color range scanable, printable or displayable
by a device; e.g., if some of the displayable colors
are outside of the gamut of the printer they cannot
be printed.
GCR
Gray component replacement. A color separation
setting used on color photographs where cyan,
magenta and yellow inks are replaced by black ink
(in a balance that would yield a gray value). The
advantages are a reduction in overall ink usage
and some increase in image detail.
Grayscale
A term for a black and white photographic image or
a scanner setting. Refers to the range of 256 gray
tones that make up the image.
Halftoning
The processes of offset printing and laser printing
are intrinsically bilevel. However, these devices
can reproduce a range of tone levels by halfton-
ing; e.g., an array of widely spaced dots produces
the perception of light gray, and an array of tightly
spaced dots produces dark gray. Halftone dots are
usually placed in a regular grid. In color printing it
is conventional to use cyan, magenta, yellow and
black grids that have exactly the same dot pitch but
different carefully-chosen screen angles.