Accessible Excel (implementation guide)

4.5. Contrasts

The selected table template provides sufficient contrast for the table contents. This also applies to "banded tables" (different coloured rows). Texts have a contrast ratio to the background of at least 4.5:1.

What is meant by this?

The contrast ratio refers to the relationship between the text and the background on which it is displayed. A high contrast ratio makes the text easier to read. A sufficient contrast ratio is achieved when the text colour stands out clearly from the background colour. The contrast ratio for normal texts is at least 4.5:1. Black text on a white background (or vice versa) represents the optimum contrast. If other colours are used, the contrast ratio must be checked.

Table templates do not always have sufficient contrast. When selecting colours, always ensure that the contrast is high enough.

Why is it important?

Sufficient contrast within a table is of great importance, especially for recipients with impaired vision. If the contrast is not high enough, the text within the table can be difficult or impossible to read, which creates barriers to accessing information.

For example, recipients with colour blindness have difficulty distinguishing between certain colours. A sufficient contrast ratio helps to ensure that they can still read the text. If the contrast ratio between the text and the background is low, it can be more difficult to read the text, even if it is large. Finally, a higher contrast ratio can also make the text easier to read on a screen in a bright light environment as it will stand out more clearly against the background.

How can I implement/check it?

If you find that your table does not correspond to the basic contrast ratio of black and white, you can either change the font colour or adjust the background colour to increase the contrast ratio. Here is a simple guide on how to do this:

1. Select the table for which you want to increase the contrast.
2. Under "Table design", select a new colour template that corresponds to the contrast ratio.
3. Alternatively, click on the "Font colour" button in the "Start" tab and select a colour with a higher contrast to the background colour.
4. Click on the "Fill colour" button in the "Design" tab and select a colour with a lower contrast to the text.
5. Make sure that the contrast ratio between text and background is at least 4.5:1.

To ensure that the contrast ratio between text and background is optimal, you can use online tools or downloadable programmes. These can automatically calculate the contrast ratio for you.

If in doubt, it is advisable to opt for a dark text (preferably black) and a light background (white), as the contrast ratio of at least 4.5:1 is always given here. It is important to note that Excel also performs an accessibility check to recognise if the contrast between text and background is too low when it is activated manually.