The Gamma component generates a gamma correction curve. When this component is used together with the Tone Curve component, it produces results identical to those of the Gamma component. This is a curve component, it can be located in the Curves category on the Components Bar.
Gamma: Map Input
Specifies the gamma value. Since Gamma is a map input, Filter Forge uses values ranging from -100 to 100 instead of the commonly accepted gamma range of 0.1 to 10. The parameter value of 0 is equivalent to gamma of 1. See Gamma Correction for the table of gamma values and their corresponding Filter Forge percentages.
Start and End: Map Inputs
Start and End define the starting and ending points of the curve. When the Start value is greater than the End value, they get reversed – the Start parameter defines the End value and vice versa. This is needed to avoid flipping the curve horizontally. Since Start and End are map inputs, their values can be controlled separately for different image areas by connecting a map component to any of these inputs.
Minimum and Maximum: Map Inputs
Minimum and Maximum define the output range of the curve. When the Minimum value is greater than the Maximum value, they get reversed – the Minimum parameter defines the Maximum value and vice versa. This is needed to avoid turning the curve upside down. Since Minimum and Maximum are map inputs, their values can be controlled separately for different image areas by connecting a map component to any of these inputs.
Invert: Map Input
Inverts the curve, converting its value at each point to its opposite: 0.05 to 0.95, 0.25 to 0.75 etc. Invert is applied to the curve before Minimum and Maximum take effect, so they still define the output range correctly. When a map component is connected to this input, the state of the checkbox is determined separately for different image areas by the brightness level of the image supplied by that component. The brightness level of 0 to 50 corresponds to unchecked Invert, and the level of 50 to 100 corresponds to checked Invert.
