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Automatic Contrast Adjustment
In automatic contrast adjustment, Nikon Scan automatically se-
lects white and black points that exclude a certain percentage
of the brightest and darkest pixels in the image, steepening curves
for enhanced contrast (the exact percentage of pixels excluded
can be specified in the Preferences dialog). By default, 0.5% of
the brightest and darkest pixels are excluded, producing a curve
that makes optimal use of the output tone range while preserv-
ing details in shadows and highlights.
Pg. For more information on:
134 Preferences—setting the "excluded" value for auto
contrast operations
Reference: The Tool Chest
To perform an auto contrast operation, click the auto contrast
button (
). The white and black points for each of the red,
green, and blue channels will be modified simultaneously (the
master curve is unaffected). Clicking the button with the Ctrl
(Windows) or option (Macintosh) key held down adjusts con-
trast only for the channel currently selected in the channel menu.
If both the brightness and color balance of the image seem to
require adjustment, click the auto contrast button to adjust both
brightness and color by creating new black and white points
based on tone information for the current crop. If you are sat-
isfied with color balance but feel that brightness and contrast
require adjustment, select the master channel and click the auto
contrast button while holding down the Ctrl (Windows) or
option (Macintosh) key. This will adjust brightness without af-
fecting the curves for the component colors.
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