9.1.1 Which font?

Font size and shape are important.

At present, books and newspapers usually use serif fonts (with tails on, like Times New Roman).

Letters, e-mails, websites, reports and other publications (like the one you are reading now) generally use sans serif fonts (without tails, like Verdana, the one used in this text).

According to the RNIB (see the previous section), anecdotal evidence suggests that sans serif fonts are preferable.

Typeface size is another key issue. RNIB research undertaken in 2006 showed that people’s reading speed increases with text size, which is not least why people who do not have sight problems will still gravitate towards publications with larger print.

The research showed that there is a 30% increase in the likelihood of fluent reading for every increase of one point beyond 10 point print. So the larger the size of your standard print, the more people will read it at their highest speed.

(Each individual, though, has an optimum print size at which their reading speed is highest, beyond which further print size increases make no difference.)

Usually the advice is to use 12 point type for standard print, and 16 or 18 point for large print. But 11 point in some fonts is bigger than 12 point in others.

The Royal National Institute for the Blind (RNIB) says that clear print documents should use ‘a very minimum type size of 12 point, or ideally 14 point’. They suggest, though, that a more accurate way of determining the best size of font to use is to measure the lower case letter ‘x’ with a ruler. The x should measure 2.3mm, with 2mm as the absolute minimum. Fonts used for large print documents should have an x-height of 2.8mm or more.

When you are choosing a font, look closely at the numbers as well as the letters. This is especially important in documents that include a lot of dates, phone numbers or financial information. In some fonts the figures 3, 5 and 8 are not very distinct, and in others 0 and 6 are easily confused. Also, some fonts show part of certain numbers below the baseline (in the way that the letters ‘g’ and ‘y’ do). This makes it harder for people to distinguish between 2 and 3, and 0 and 9, especially in tables.