Contex Chroma 3040, Operator'S Manual

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3-2 Operating Modes
3.4 Graytone mode
In Graytone mode, the actual graylevel of each pixel is scanned; 256
levels are recognized, corresponding to 1 byte (8 bits) per pixel. This
results in graytone files that are 8 times larger than uncompressed
files scanned in Line mode at the same resolution; for example, an E-
Size drawing scanned in graytone mode at 300 dpi has a file size of
150 MByte, compared with typical 0.4 -1.0 MByte for a compressed file
in Line mode.
3.5 B/W modes
In this mode, the MAGNUM Color Scanner outputs each scanned pixel
as a single bit, either black (1) or white (0), depending on whether its
gray level is below or above the threshold.
Both fixed level and 2D-Adaptive thresholding are supported.
3.6 B/W Copy Modes
The copy modes incorporate Dual 2D-Adaptive processing with
different combinations of ADL+ Error Diffusion Halftoning, 2D-
Background suppression, 2D-Auto edge enhancement and 2D-
Adaptive thresholding. The copy modes are ideal scanning wide
format documents that are intended for re-printing. The ADL+ Error
Diffusion Halftoning supports visibility of graytones in printed output by
adding toned shades of gray in regions between black and white. The
copy modes are described in the table below:
Copy Mode Image Processing Usage
B/W Copy
Normal ADL+ Error diffusion halftoning
2D-Auto edge enhancement
2D-Adaptive background
suppression Halftone copy to print of all
normal originals
B/W Copy
Adaptive ADL+ Error diffusion halftoning
2D-Adaptive thresholding
2D-Adaptive background
suppression Halftone copy to print of Sepia,
Blueprint and other originals
with heavily distorted
foregrounds and backgrounds
where the shades making up
the image “noise” are close to
the shades making up the
image’s data and hard to
differentiate.
B/W Copy
Photo ADL+ Error diffusion halftoning
Halftone copy to print of
continuos shades of gray such
as in photos.