The graphical message’s legibility is determined by the technical design of the text
and the pictures, that is, their clarity. Legibility can bemeasured rather objectively,
and its quality may very well be assessable whether we understand its content or
not. (This is noted in the next sub-section.)
1.7.3.1 Legibility of text
As far as the text is concerned, we should avoid unusual typefaces, as well as typefaces
that are too small or too large. Typeface and font size must be adapted partly
to the medium and partly to the choice of technical production.We read words in
a text as “pictures”, not letter by letter. In a book it might be sufficient to set the
type between nine and twelve points, although on a display screen, the text should
be at least three to five times as large. The text on a poster meant to be read from
some distance may need to be ten times greater in size. Here is an example of a text
with rather poor legibility: