Color Correction - Nuke 101: Professional Compositing and Visual Effects - page 170

Color Matching with the Grade Node
The Grade node is specifically built to make some color correction operations easier. One
of these operations is matching colors from one image to another.
When matching colors, the normal operation is to match black and white points between
the foreground and background (only changing the foreground), and then match the level
of the midtones gray, and finally match the midtone hue and saturation.
Using the Grade node
The Grade node is made out of a few of the building blocks mentioned earlier. TABLE 4.2
shows a list of its seven properties.
Table 4.2. Grade Node Properties