Gamma Sheet - Canon CanoScan N650U User Manual

chapter 4
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Gamma Sheet

When the Gamma button is clicked, the Gamma sheet is displayed.
Gamma refers to a process where mid-tones are shifted so that the
lighter colors are lightened and darker colors are darkened. For example,
let us say you scanned a photograph of a subject in a boat in a tree-lined
lake and the shadows of the trees are dark enough and the white of the
boat is light enough, but the blue in the sky, the blue of the water, and
the blue of the subject's clothing all look the same. By increasing the
Scanner Gamma value of the image, the sky might become lighter and
the water darker, giving a better contrast to the image. The Monitor
Gamma value is a reciprocal number of the Scanner Gamma value.
Channel
If you want to select one of the primary colors (RGB) for adjusting the
gamma value, click the Channel down-arrow and select the color or
leave the settings at Master to adjust all the colors.
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