There are three term to consider with colour correction: Hightlights, Midtones, Shadows.
Grade
Grade node is one of the most powerful nodes in Nuke, it can be used to white-balance the image sequences by sampling the whitepoint and blackpoint; change the darkest(shadows) and lightest area(highlights) by adjusting lift and gain. Gamma can be used to grade midtones. We can also choke the image by adjusting gamma through alpha channel.
We always grade the unpremulted images, so we need to unpremult the image firstly if necessary, then premult it after grading. We need the premulted images for assets added on the background before compositing.
More info see:
https://learn.foundry.com/nuke/content/reference_guide/color_nodes/grade.html?Highlight=grade
https://learn.foundry.com/nuke/content/reference_guide/merge_nodes/premult.html?Highlight=premult
ColorCorrect
ColorCorrect is a more precise node compared to grade node, it can be used to modify the shadows, midtones and highlights. Here offset is used to grade shadows, similar as lift in grade node.
We can modify the region curves to change the particular regions that we want to control.
Colour matching plates
In order to create compositing more naturally, it is necessary to control the colour settings for the elements. I chose 2 still images to try this task as follows:
Original images:
White-balancing is the first step of the colour matching, by choosing both the darkest and brightest points when viewing in Luminance mode (shortkey y), as well as adjusting gamma parameter until I find no difference before and after grading the images.
Then I used Grade node to match the colour of the two images, by adjusting lift and gain parameters to match the shadow and highlight respectively.
Review:
The two original images are not matched so properly due to other factors such as lighting and angle of shot, which should be taken into consideration before compositing.