The Convert to Grayscale node converts color  to the gamma.

Figure 1: Apply gamma curve Node

Parameters

    • Enabled - Whether this layer is applied or skipped.
    • Attach to layer - When selected, this layer modifies the input of the next lower layer that is not itself attached to a layer. Otherwise, it applies to the output of the next lower layer.
    • Gamma - The gamma value used. The equation applied is: output = pow(input, 1/gamma).
    • Opacity - The opacity channel used to control the transparency of this layer.
    • Blend mode - The blend mode used to mix the RGB values of this layer with those of the background.