Dos and Don’ts of Data Visualisation

Don't use more than (about) six colours

Colour categorisation is not random, and the centres of basic colour terms are very similar in all languages. Using colour categories that are relatively universal makes it easier to see differences between colours. The figure below shows the order of appearance of colour names in languages around the world. The order is fixed, with the exception that sometimes yellow is present before green and sometimes the reverse is the case.

Use different colours to represent different categories (e.g., private/public, types of pollutant), not different values in a range (e.g., age, temperature). See qualitative colour palette below.

If you want colour to show a numerical value, use a range that goes from light to dark in one of the universal colour categories. See sequential colour palette below.

If you need to represent diverging numeric values (from hot to cold, from good to bad, etc.), use two colours as shown in the diverging colour palette example.

Do not use rainbows for range values.