In science and color theory there are precise definitions for contrasting and complementary colors and how they appear on the color wheel. In graphic design and some other fields we use a looser interpretation. Colors 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.
You may also see these opposite colors referred to as complementary colors which generally refers to each of a pair of colors that are directly are almost directly opposite each other on the color wheel, such as purple and yellow.
Red and green are contrasting colors. The more transitional colors separating two colors, the greater the contrast. For example, magenta and orange is not as high contrast a pair as magenta and yellow.
Colors that are directly opposite from one another are said to clash -- although this clashing or high contrast is not necessarily a bad thing. Some of these high contrast, complementary, clashing colors are quite pleasing.
Using Contrasting Colors
Common color combinations that use two, three, or four contrasting colors are described as complementary, double complementary, triad, and split-complementary color schemes.
Each additive primary color (RGB) pairs up nicely with a complementary subtractive (CMY) primary color to create pairs of contrasting colors. Vary the shades for additional complementary colors with less contrast.
- Red (additive) and aqua/cyan (subtractive)
- Green (additive) and fuchsia/magenta (subtractive)
- Blue (additive) and yellow (subtractive)