Complementary Colours
Pairs of colours sitting opposite each other on the colour wheel, which produce maximum contrast when placed together.
In depth
Opposite pairs — blue and orange, red and cyan, yellow and violet — reinforce each other, each making the other appear more intense. The orange-and-teal pairing is so widely used in cinema precisely because skin sits naturally in the orange range, so pushing shadows toward teal separates a subject from the background almost automatically.
Examples in practice
A subject in a warm-toned coat against a deep blue evening sky reads with immediate separation.