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HD Ultra X Service Guide
Photographers and printers measure transmission in base-10 logarithmic density units, where
transmission of unity corresponds to a density of 0, transmission of 0.1 corresponds to a density of 1,
transmission of 0.01 corresponds to a density of 2, and so on.
Density
The light stopping ability of a film. Density is inversely proportional to the amount of light reflected or
transmitted by an image.
Device Dependent Color Space
For example RGB. A device dependent color space, e.g., the same scan file will appear different when
viewed on different computer displays. For example CIE LAB. A device independent color space is one in
which color values are absolute, e.g., defined by CIE standard. CIE LAB is the central color space in color
management systems (CMS) and is used to translate between different device dependent color spaces
such as scanner RGB and display RGB.
Device Profile
A file used as part of a Color Management System (CMS). A device profile contains information about the
characteristics of a scanner, computer display or printer. The format for device profiles (Win95, Colorsync.
etc.) is standardized by ICC (International 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 device
pixel. However, if the viewer is sufficiently distant from the printed page or display, the value of
neighbouring pixels can be set so that the viewer's eye integrates several pixels to achieve an apparent
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 individual 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-
fly. The separate enhancement processes are simultaneously performed on different drawing aspects.
Dynamic Range
A measurement of scanner quality; the density difference between highlights and shadows.
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