Using Colour


“avoiding catastrophe becomes the first principle in bringing color to information: Above all, do no harm.”

Envisioning Information, Edward Tufte, Graphics Press, 1990


Using Colour

  1. Physics of colour

  2. Practicalities of colour

  3. Accessibiilty of colour


1. Physics of Colour

Colour is ‘visible light’


Describing colour:

i. Hue, lightness, and colorfulness

ii. RGB

Background matters:

Colors look darker and smaller against white and lighter and larger against black.

Use a consistent background colour

Simultaneous contrast can make the same colors look different

Simultaneous contrast can make different colors look the same

Ensure background contrasts with text and data colours


2. Practicalities of Colour

Use color to communicate information

Colour !- decoration / wallpaper.

Different colors should correspond to different meanings


Three main uses of colour to promote communication:

• To highlight particular data

• To group items (categories)

• To encode quantitative values (sequential or diverging)

i. Use soft, natural colors to display most information and bright and/or dark colors to highlight information

ii. Use colours of the same hue to group/categorise data

Fig A example categorical map from the US census of 2000.

iii. Use colours of increasing/decreasing brightness or colorfulness to illustrate quantitative data


Fig. A map of precipitation with a sequential lightness-hue ramp from

iv. Use colours of increasing/decreasing brightness or colorfulness to illustrate quantitative data


Fig A map of temperature anomaly form

v. Use light colours for non-data components

Component Default Color
Axis lines Thin gray lines of medium intensity.
Borders If needed, thin gray lines of medium intensity.
Background Use white or ‘None’

Some suggestions for data components of graphs


3. Accessibility of Colour

Red-green colourblindness affects:


i. Use colour and symbols

ii. Keep colours minimal

iii. Avoid problem colour combinations



Use colorbrewer to help with everything!



Few, S. 2008. Practical Rules for Using Color in Charts

MacDonald, L.W. 1999. Using Color Effectively in Computer Graphics