Grade

Performs a simple per-channel colour grading operation as follows :

A = multiply * (gain - lift) / (whitePoint - blackPoint) B = offset + lift - A * blackPoint result = pow( A * input + B, 1/gamma )

See the descriptions for individual plug for a slightly more practical explanation of the formula.

user

Container for user-defined plugs. Nodes should never make their own plugs here, so users are free to do as they wish.

out

The output image generated by this node.

enabled

Turns the node on and off.

in

The input image

channels

The names of the channels to operate on. Names should be separated by spaces and can use Gaffer’s standard wildcards.

processUnpremultiplied

Unpremultiplies data before processing, and premultiply again after processing. This allows accurate processing of nodes that deal with color, when running on partially transparent or deep images.

blackPoint

The input colour which is considered to be “black”. This colour is remapped to the lift value in the output image.

whitePoint

The input colour which is considered to be “white”. This colour is remapped to the gain value in the output image.

lift

The colour that input pixels at the blackPoint become in the output image. This can be thought of as lifting the darker values of the image.

gain

The colour that input pixels at the whitePoint become in the output image. This can be thought of as defining the lighter values of the image.

multiply

An additional multiplier on the output values.

offset

An additional offset added to the output values.

gamma

A gamma correction applied after all the remapping defined above.

blackClamp

Clamps input values so they don’t go below 0.

whiteClamp

Clamps output values so they don’t go above 1.