Xerox DocuMate 3125 User Manual page 142

Scanning from TWAIN and WIA
Black background scanners:
Some scanners have a black background plate. A black background results in more precise
cropping results and skew detection. However, when scanning thin paper, such as multipart
color forms or ruled writing paper, which are less than 18lb paper weight, the background may
"bleed" through into the final image and make the image darker than it should be. In that case,
try adjusting the brightness level between 60% and 80%.
Contrast
Contrast refers to the differences between the light and dark portions in the image. Move the
slider left or right to decrease or increase the contrast levels. Increasing the contrast level
emphasizes the difference between the lighter and darker portions of the image, decreasing the
contrast de-emphasizes that difference.
Choosing contrast values
While Brightness adds the same amount of gray or white to all pixels in the image, Contrast
adjusts the pixels based on the pixel color level. For instance, increasing the contrast level will
add white to light colored pixels and gray to dark pixels to make the difference between color
levels in the image crisper. Decreasing the contrast level will have the opposite affect, where
light colored pixels are modified with gray and dark pixels are modified with white to make the
transition of colors in the image appear smoother.
Adjusting the contrast level is based on how you want the image to appear and there is no
standard to adhere to. Contrast works in conjunction with brightness for image enhancement,
when decreasing the brightness level, the overall image becomes darker, in which case you may
want to increase the contrast level so that the differences between the lighter and darker
portions of the image are clearer.
Below are some recommended options for contrast image correction based on the original
document quality.
• Original documents of good quality - 50%
• Pencil written letters, forms, or drawings - 55% to 65%
• Faded pictures or old documents with faded text - 60% to 70%
• Light colored carbon copy paper, such as yellow or pale pink or pale green, with light text -
45% to 55%
• Newspaper or magazine pages - 55% to 70%
• Book pages - 60% to 75%
• Pictures taken inside or in the shade - 40% to 60%
User's Guide
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Xerox DocuMate 3125
7-134