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Chapter 13 Special FX
Linking of Hue and Saturation
This function allows you to modify Hue and Saturation simultaneously but only in the Ve c t o r D i s p l a y
( page 754). The Ve c to r D i s p l a y is automatically called when you click this button.
The mouse pointer changes on the Ve c t o r D i s p l ay. If you drag the mouse pointer:
 In a circular motion, the color locuses rotate around the axis intersection, i.e. the Hues change;
 Up and down, the Saturation rises/falls.
 Simultaneously hold down the SHIFT key to change only the Saturation; hold down CTRL
to change only the Hue.
Contrast
“Contrast” is the difference between the brightest and darkest spots in an image. When the difference is
minimal, the image is “flat”; when it’s extreme, the contrast is “hard”. A black silhouette against a bright
white backdrop is about the hardest contrast imaginable. Once contrast is used as a means for designing
images, however, the subjective perception of differences between bright and dark is what matters most.
Contrast can be modified in two ways: Black-Gamma-Gain control and Contrast Adaptation.
Black-Gamma-Gain Control
Contrast can best be increased by making the brightest spots in an image a little brighter and the darkest
spots a little darker (and vice versa to reduce contrast).
This is achieved with a slight increase or reduction in Gain and a concurrent slight reduction or increase
in Black. Basically, this applies both to the luminance component and the RGB components.
Saturation also contributes to the subjective perception of contrast.
Contrast Adaptation
This function automatically adapts the contrast based on the brightest and darkest spots in an image:
Activate the function and drag a line from the “black point” to the “white point” (i.e. from the darkest to
the brightest point in the image). Because this can be a matter of individual pixels, it may be helpful to
activate the Zoom ( page 739).
Y Gain and Y Black are modified so that the luminance value of the “black point” is set to true black (Y=0
or Y=16) and the luminance value of the “white point” is set to true white (Y=255 or Y=235).