Gamma Node

The Gamma node enables you to correct the gamma of an image. Gamma is an objective measure of the contrast in an image, equal to the slope of the characteristic curve. The characteristic curve, or gamma curve, is a plotted curve that illustrates the change in density of a negative as exposure increases.

The Gamma node performs the following computation (where V is the color value of a pixel):

V = V
1.0/Gamma

Gamma Parameter Tab

Gamma

You set the Gamma parameter by keying in a numerical value in the preferred range of 0.1 to 4.0 (though the parameter is unconstrained) or by using the mouse to set the tuner to the desired value. The default value is 1.0.

Channel Mask

The Channel Mask parameter enables you to inhibit the modification of any channel by deselecting the Red, Green, Blue, Alpha, or Other channel icons.

Control Image Parameters

The Control Action and Control Channel menus enable you to specify how an optional control image input will govern the node operation, as explained in "Using Control Images with Filter Nodes ."




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