This menu selection allows you to assign the assumed gamma value for an image, and to set the default for a file type (so that any files loaded with the given type will be assumed to be adjusted for that gamma value).
Image gamma value. Use the arrows or the mouse to change the assumed gamma value. Select a value of zero (0.0) to turn off gamma correction for this image (or for the current file's file type, if Set default for type is enabled).
Save for this image. Check this option to store the selected gamma value in the database for this image, so that whenever it is loaded it displays using this gamma.
Set default for type. Check this option to assume the selected value as the default for any loaded images of the current file's file type.
Auto view. Check this option to make the gamma change automatically visible each time you adjust the value. This option is always on if your display driver is set to use palette-based (256-color) color setting .
Default. Click this button to restore the previous default gamma value for this file type.
View. Click this button to view the gamma correction if Auto view is unchecked.