The Colour Theory

Two colours from different segments of the colour wheel are contrasting colours. For example, red is from the warm half of the colour wheel and blue is from the cool half. They are contrasting colours.

In science and colour theory there are precise definitions for contrasting and complementary colours and how they appear on the colour wheel. In graphic design and some other fields we use a looser interpretation. Colours don't have to be direct opposites or have a set amount of separation to be considered contrasting or complementary. In design it's more about perception and feeling. And attracting the eye of the viewer.

You may also see these opposite colours referred to as complementary colours which generally refers to each of a pair of colours that are directly are almost directly opposite each other on the colour wheel, such as purple and yellow.

Reds and greens are contrasting colours. The more transitional colours separating two colours, the greater the contrast. For example, magenta and orange is not as high contrast a pair as magenta and yellow or magenta and green. I really like the combination of red and green and will try using these contrasting colours to attract the eye of my audience in the production of my magazine review.