1. General

1.3. Colours for conveying information

When colours are used to convey information (e.g. in diagrams or to mark text), labels, symbols or patterns convey the same information.

What is meant by this?

It is recommended that information is not only represented by colours, but also by labels, symbols or patterns. This means, for example, that colour AND pattern should be used in a diagram to represent a bar. For example, buttons in the colours green and red are also described with "yes" and "no". This creates opportunities for the information to be better perceived visually.

Why is it important?

If information is presented exclusively through colours, recipients who do not perceive all colours clearly may have difficulty understanding this information. There is a risk that information that is only conveyed via colours will be lost on such groups of people. For example, recipients with colour vision deficiency have difficulties perceiving certain colours or contrasts. Colours with the same saturation can prevent full perception of what is shown and result in not all information being absorbed. Grey contrasts should also only be used to a limited extent, as recipients with colour vision problems may have difficulty recognising certain shades of grey or differences in brightness.

Through the additional use of labels, symbols or patterns, information can be presented in several ways to ensure that it is also accessible to groups of people who work independently of the colour display, are distracted by bright colours or perceive stimuli very strongly.

How can I implement/check it?

For example, to add a pattern to a chart in Excel, you can proceed as follows:

  1. Click on the part of the diagram that you want to add a pattern to.
  2. Click on "Format" and the small arrow in the right-hand corner, next to the "Shape types" tab.
  3. A new window opens on the right-hand side for formatting the diagram.
  4. Click on the symbol of the small colour bucket "Fill and lines".
  5. Select "Pattern filling" and choose a desired pattern and the desired colours.

You should also add a label/axis title to each chart in Excel and proceed as follows:

  1. Select the desired diagram with the mouse and click on the large plus symbol on the right.
  2. If you activate the "Axis titles" option here, these will appear on the diagram.
  3. Now double-click with the left mouse button on one of the two axis labels.
  4. You can now change the lettering and its size, font and colour, among other things.
  5. If you hold down the axis title with the mouse, you can move it to another location. You can also delete the axis labels in this way.

Diagrams and other representations should be viewed in different ways to check accessibility, for example by hiding colours or changing the brightness to ensure that the information is easy to understand regardless of colour. There are various ways to do this.

Print the respective page in greyscale to get an idea of how your displays look without colours. In addition, you can set the brightness of your end device from "very high" to "very low" and check whether the information is still accessible.