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.