Nikon Scanners Software Reference Manual page 167

Chapter 16
Red/Cyan gamma curve button: the top-most button in the center of the
Gamma Curve Editor dialog, allows adjustment of the red-to-cyan gamma curve.
The Green/Magenta gamma curve button: immediately below the Red/Cyan
button, allows adjustment of the green-to-magenta gamma curve.
The Blue/Yellow gamma curve button: immediately below the Green/Magenta
button, allows adjustment of the blue-to-yellow gamma curve.
Windows:
Red gamma curve button: the R button in the Gamma Curve Editor dialog,
allows adjustment of the red gamma curve.
Green gamma curve button: the G button in the Gamma Curve Editor dialog,
allows adjustment of the green gamma curve.
Blue gamma curve button: the B button in the Gamma Curve Editor dialog,
allows adjustment of the blue gamma curve.
These controls are only active when a color film type is selected in the Scan dialog.
You will notice that changes to the shape of the gamma curves will cause corre-
sponding changes to the tonal quality of the image, as seen in the adjacent image pre-
view window. As the curved is altered, a curve-fitting software algorithm redraws the
new curve.
As mentioned earlier, the bottom portion of the gamma curve corresponds to the
image's shadow areas. The middle portion corresponds to the image's midtones, and
the top portion to the highlights. An example is shown in Figure 16.26, in which the
original gamma curve is shown as the lighter line. Two marker points were placed on
this gamma curve, one in the shadows region of the curve and one in the highlights
region of the curve. By moving the highlight marker to the right and the shadow mark-
er up and to the left, the gamma curve is redrawn and shown as the darker curve.
Software Reference for Scanners
The Gamma Curve Editor Dialog
Page 153