Gamma Sheet - Canon CanoScan D1250U2F User Manual

chapter 3
What is on the
screen?
Contents
Glossary
Index

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) to adjust the gamma
value, click the Channel down-arrow and select a color or leave the settings
at Master to adjust all the colors.
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