Xerox Xerox DocuMate 4790, User Manual

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Scanning from TWAIN and WIA
Xerox
®
DocuMate
®
4790
User’s Guide
7-139
Error diffusion, Bayer, and Halftone pattern
Error diffusion , Bayer , and Halftone patterns are the intentional application of noise (dithering) in the image to
help alleviate banding when scanning in binary (black and white) mode. For example, if you scan a color photo in
black and white, the image file will have large blocks of black and white and the image barely recognizable.
Dithering the image creates a black and white image that is recognizable.
Below is an example of a color scan, a black and white scan without dithering, and a black and white scan with
dithering. When the image is scaled down, it may look like a grayscale scan. When the image is at normal size or
enlarged you will be able to clearly see the dithering pattern, as shown in the close-up image.
Bayer dither scan - Close up
Mixed Content Options (Text and Graphics)
If the documents you are scanning contain both text and graphics, select one of the mixed content options. The
driver will evaluate the image for sections of graphics and text, and then apply threshold and a dither pattern to
the appropriate sections in the image.
Fill Margin Holes
Select this option if you are scanning pages with punched holes in the margins. This option will fill these holes
with the detected background color in the final scan. The scanner will detect and fill the holes under the
following conditions:
• The size of the hole can be between approximately 4 mm and 12 mm
• The maximum width of the margin is 25.4 mm from the edge of the paper
Color scan
Black and White scan Bayer dither scan