C_ColourMatcher aims to produce a global gain-based color correction across all the views in a rig to balance out differences in exposure and white balance. It solves across all cameras to find the minimum required gain changes to ensure color similarity.

Note:  C_ColourMatcher does not compensate for color shifts not resulting from exposure- or gain-type differences. It also does not deal with gamma- or offset-type differences.

Color matching relies on solve data and should be performed before stitching the solved camera output together, so ideally, place C_ColourMatcher between C_CameraSolver and C_Stitcher.

Tip:  CaraVR contains an example end-to-end workflow in Nuke's toolbar under CaraVR 2.1 > Toolsets > Full Pipeline.