Typography is the design and layout of a printed page and especially the setting and arranging of type on the page. It has a major impact on how inspired we are to read text and how far into it our interest carries. Although typography also creates images in a reader’s mind, its key purpose is to render the text into a pleasant, easy-to-read and attractive form.
Readability is affected by a great number of typographic factors. The first of them is sufficient font size. There is no universally applicable guideline for font size, but generally, for books, the point-size of body text is 9.5–12pt. Choices in this respect depend on such aspects as column width, clarity and proportions of the typeface, and the age of the intended readers.
It is good to avoid unnecessary use of uppercase letters in, for example, headings. Uppercase letters form a uniform string of equal height, out of which the letters are hard to distinguish.
Subheads serve as small breathers for the readers in the reading process and steer them in the text. Typographically, the subheads have to be clearly distinguished from the body text, but they shouldn’t be excessively highlighted either.
Reading takes place in small leaps, the eye picks out 5–10 characters at a time. 50–70 characters per line is usually considered an appropriate line length for books. Consequently, it is important to adapt the line spacing according to the applied line length. Line length and line spacing are inseparable: when one changes, the other has to be changed too.
Paragraph changes need to be indicated in some way, and with book text this is done by indenting the first line of a new paragraph – not by adding an extra line spacing. Empty lines break up a normal text column and take up space unnecessarily, interrupting the flow of reading.
Click on any image to enlarge these typesetting examples: