Typefaces and Legibility
The choice of font can affect the legibility of text, both printed and on a screen. The character shape, text format and layout can enhance or detract from the intended meaning. In general, legibility is higher with simple "open" typefaces.

Use a typeface such as tiresias infofont, which clearly differentiates numerals and letters.
The contrast and colour of text and background also affect legibility; this can be a severe problem for people who are colour blind.
At larger print sizes, most visually impaired users benefit from having white or yellow print on a dark matt background.
However, at small print sizes, it is better to use black print on a white background.
More detailed information is provided in the guideline on typefaces.