The colour wheel is the most important tool for understanding colour contrast. The tradition of modeling colours like this goes all the way back to Isaac Newton, and most of us were first introduced to it in grade school.

Contrasting colours are those that lie directly opposite each other on the wheel—like red and green, orange and blue, or yellow and purple. When contrasting colours are placed next to one another, each appears brighter and more intense. When they are blended, they neutralise each other.

To create colour contrast, choose one from the “dark” half of the wheel—the home of reds, blues, and purples. The other colour will be from the “light” half, where the yellows, oranges, and greens live.

Now lighten the light colour, and make the dark colour darker, and you’ve created maximum contrast! The colours play off each other in a way that seems natural—but it’s just the laws of colour contrast at work.