Nikon 9235 - Coolscan III Reference Manual page 122

The controls in the Gamma tab are only active if Nikon CMS is
off, when they are used to adjust data from the scanner so that
they display correctly when previewed on your monitor or
opened in another application.
Reference: Preferences
The Gamma Tab
• Preview gamma
Preview gamma applies to the image displayed in the preview
area of the scan window. In general, preview gamma is solely
for display in the preview area and does not apply to the
image data that are passed to the host application when the
Scan button is clicked. There are two exceptions to this
rule, however. The first is when Nikon Scan is used as a
stand-alone application, the second when Use preview
gamma is selected as the main scan gamma option. In these
cases preview gamma is applied to image data passed to the
host application.
Preview gamma defaults to a value of 1.8 on the Macintosh,
2.2 on Windows computers. To choose a setting suited to
your monitor, adjust the value so that the patterns of gray
lines and dots above the slider match in density. Gamma can
be set by entering a value directly into the text box or by
moving the slider. When making this adjustment, set the reso-
lution on your monitor to a low value such as 640 480 and
sit as far away from the monitor as possible. To restore the
default setting for your platform, click the Reset button.
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