User Manual

Xerox
®
DocuMate
®
3125 Scanning from TWAIN and WIA
7-135 User’s Guide
Color image contrast examples
The examples below show the original image at the default setting of 50% contrast level, 25%
contrast and 75% contrast.
Technical note:
Most monitors have a contrast setting that is user adjustable. When viewing scanned images
on-screen, versus printing the image, the contrast setting of the monitor may affect how clear a
scanned image looks when compared to the original. If the scanned image is too different from
the original image, or if adjusting the scanned contrast level does not modify the image how
you want, try adjusting the monitor's contrast level. Refer to the monitor's user guide for
adjusting the contrast level and see if the manufacturer has any recommended settings.
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 carbon copy
paper 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 40% and 60%, then adjust the contrast level
between 60% and 80%.
Gamma
Gamma is the tone curve and starting point for image enhancement. Move the slider left or
right to darken or lighten the image. As you raise or lower the Gamma value, the values at
which Brightness and Contrast affect the image are changed. It is recommended that you
keep the default gamma value, or adjust this setting before adjusting the other options.
Choosing gamma values
As the gamma value is adjusted lower, the tone curve begins to straighten and the shadows of
the image are expanded, darkening the shadows without overall darkening the image with gray
as seen with lowering the brightness level. This way, the highlights and shadows in the image
are maintained by saturating the pixels with darker levels of the same color rather than adding
gray to all colors.
As the gamma value is adjusted higher, the tone curve bends and the highlights of the image
are expanded, lightening the highlights without overall lightening the image with white as seen
with raising the brightness level. This way, the highlights and shadows in the image are
maintained by saturating the pixels with lighter levels of the same color rather than just adding
white.
Contrast: 25% Contrast: 50% Contrast: 75%