Microtypography
Microtypography is the name given to a range of methods for improving the readability and appearance of text, especially justified text. The methods reduce the appearance of large interword spaces and create edges to the text that appear more even.
Methods
There are several methods that can be used.
The tracking (interletter, as opposed to interword, space) can be increased or decreased.
The width of glyphs can be increased or decreased.
- These methods are sometimes called expansion. Robert Bringhurst (Bringhurst 2008) suggests about 3% expansion or contraction of intercharacter spacing and about 2% expansion or contraction of glyphs as the largest permissible deviations.
- Compare Kashida in Persian typography.
Glyphs that are small (such as a period) or round (such as the letter "o") at the end of a line can be extended beyond the end of the line to create a more even line at the edge of the text. This is called protrusion, margin kerning, or hanging punctuation.
Multiple different versions of the same glyph with different widths may be used. This method was used by Gutenberg in the 42-line bible (see (Zapf 2007)), but is less easy now because few fonts come with multiple versions of the same glyph. It is not practical with narrow variants of a font or with different weights of a font because the glyphs look too different from each other to create good effect. It is possible with some multiple master fonts.