Primary colour: This is the main colour of the page. It will occupy most of the area, and set the whole "feel" of the design. Secondary colour: This is the second colour on the page, and it is usually there to "back up" the primary colour. It is usually a colour that is pretty close to the primary colour. Highlight colour: This is a colour that are used to emphasis certain parts of the page. It is usually a colour which constrast more with the primary and secondary colour, and it should be used with moderation. It is common to use a complimentary or split complimentary colour for this.

By now you should recognize the colour wheel. If not, please read the section "what are colours?". As mentioned there the colour wheel is very useful when you want to combine colours in a way that is pleasing. Below I show some of the most common ways to combine the colours in the colour wheel.

The analogue colours are the colours which lies on each side of any given colour. Often these are colour schemes found in nature. The most widely used analogous colour scheme is the one marked to the left - red, orange and yellow. A site that take use of analogous colours usually feels harmonious. The secondary colour, as described above can often be an analogous colour.

The complementary colours are the colours which are directly opposite to each other in the colour wheel. The complementary colours are contrasting and stands out against each other. Often it is a good idea to use a complementary colour as the hightlight colour.

Split complementary is a colour and the analogous colours to its complement color. Using split complementary colours can give you a design with a high degree of contrast, yet still not as extreme as a real complementary colour. It also results in greater harmony than the use of the direct complementary.

Triad colours are three hues equidistant in colour wheel. When you want a design that is colourful and yet balanced, a triad colour scheme might be the way to go.

Besides from the colour combination described above which are based on the position of the colours in the colour wheel, there are also a few other ways of combining colours.

A monotone colour scheme is just one single hue and its variations in terms of tints, shades and saturation. Using saturation and tint/shade variations of a colour is always good. However in most cases I would advice against using a fully monotone scheme, as there is a big risk of monotony. Using it with pure white or black can be efficient though.

A monotone acromatic colour scheme is a special instace of the monotone scheme which consists of only neutral colours ranging from black to white. A scheme like this can be efficient, but it can very easily look boring. Using an acromatic scheme with just one bright colour for highlight can be very effectful.

Now that we know how different colours can be combined, we just need to introduce one more important aspect of colour theory, and that is contrast. Simply put contrast is the difference between two colours.