Typographers have developed a comprehensive vocabulary for describing the many aspects of typefaces and typography. Some vocabulary applies only to a subset of all
scripts. Serifs, for example, are a purely decorative characteristic of typefaces used for European scripts, whereas the glyphs used in Arabic or East Asian scripts have characteristics such as stroke width that may be similar in some respects but cannot reasonably be called serifs and may not be purely decorative.
Serifs Typefaces can be divided into two main categories:
serif and
sans-serif.
Serifs comprise the small features at the end of strokes within letters. The printing industry refers to typeface without serifs as sans serif (from French , meaning without), or as (or, in
German, ). Great variety exists among both serif and sans-serif typefaces. Both groups contain faces designed for setting large amounts of body text, and others intended primarily as decorative. The presence or absence of serifs represents only one of many factors to consider when choosing a typeface. Typefaces with serifs are often considered easier to read in long passages than those without. Studies on the matter are ambiguous, suggesting that most of this effect is due to the greater familiarity of serif typefaces. As a general rule, printed works such as newspapers and books almost always use serif typefaces, at least for the text body. Websites do not have to specify a font and can simply respect the browser settings of the user. But of those web sites that do specify a font, most use modern sans-serif fonts, because it is commonly believed that, in contrast to the case for printed material, sans-serif fonts are easier than serif fonts to read on the low-resolution computer screen.
Proportion A
proportional typeface, also called
variable-width typeface, contains glyphs of varying widths, while a
monospaced (
non-proportional or
fixed-width) typeface uses a single standard width for all glyphs in the font.
Duospaced fonts are similar to monospaced fonts, but characters can also be two character widths instead of a single character width. Many people generally find proportional typefaces nicer-looking and easier to read, and thus they appear more commonly in professionally published printed material. For the same reason,
GUI computer applications, such as
word processors and
web browsers, typically use proportional fonts. However, many proportional fonts contain fixed-width (tabular) numerals so that columns of numbers stay aligned. Monospaced typefaces function better for some purposes because their glyphs line up in neat, regular columns. No glyph is given any more weight than another. Most manually operated
typewriters use monospaced fonts, and a typeface that looks like it was typewritten is sometimes referred to as a typescript. So do
text-only computer displays and third- and fourth-generation game console graphics processors, which treat the screen as a uniform grid of character cells. Most computer programs which have a text-based interface—
terminal emulators, for example—use only monospaced fonts or add additional spacing to proportional fonts to fit them in monospaced cells in their configuration. Monospaced fonts are commonly used by
computer programmers for displaying and editing
source code so that certain characters, for example
parentheses used to group arithmetic expressions, are easy to see.
ASCII art usually requires a monospaced font for proper viewing, with the exception of
Shift JIS art which takes advantage of the proportional characters in the
MS PGothic font. In a
web page, the <tt> </tt>, <code> </code> or <pre> </pre>
HTML tags most commonly specify monospaced fonts. In
LaTeX, the
verbatim environment or the
Teletype font family (e.g., \texttt{...} or {\ttfamily ...}) uses monospaced fonts (in
TeX, use {\tt ...}). Any two lines of text with the same number of characters in each line in a monospaced typeface should display as equal in width, while the same two lines in a proportional typeface may have radically different widths. This occurs because in a proportional font, glyph widths vary, such that wider glyphs—typically those for characters such as W, Q, Z, M, D, O, H, and U—use more space, and narrower glyphs—such as those for the characters i, t, l, and 1—use less space than the average. In the publishing industry, it was once the case that editors read
manuscripts in monospaced fonts—typically
Courier—for ease of editing and word count estimates, and it was considered discourteous to submit a manuscript in a proportional font. This has become less universal in recent years, such that authors need to check with editors as to their preference, though monospaced fonts are still the norm.
Font metrics to illustrate the concepts of
baseline,
x-height, body size, descent and ascent|class=skin-invert-image Most
scripts share the notion of a
baseline: an imaginary horizontal line on which characters rest. In some scripts, parts of glyphs lie below the baseline. The
descent spans the distance between the baseline and the lowest descending glyph in a typeface, and the part of a glyph that descends below the baseline has the name
descender. Conversely, the
ascent spans the distance between the baseline and the top of the glyph that reaches farthest from the baseline. The ascent and descent may or may not include distance added by accents or diacritical marks. In the
Latin,
Greek and
Cyrillic scripts, sometimes collectively referred to as LGC, one can refer to the distance from the baseline to the top of regular lowercase glyphs, known as the
mean line, as the
x-height, and the part of a glyph rising above the x-height as the
ascender. The distance from the baseline to the top of the ascent or a regular uppercase glyphs, known as the cap line, is also known as the cap height. The height of the ascender can have a dramatic effect on the readability and appearance of a font. The ratio between the x-height and the ascent or cap height often serves to characterize typefaces. Typefaces that can be substituted for one another in a document without changing the document's text flow are said to be "metrically identical" or "metrically compatible". Several typefaces have been created to be metrically compatible with widely used proprietary typefaces to allow the editing of documents set in such typefaces in digital typesetting environments where these typefaces are not available. For instance, the free and open-source
Liberation fonts and
Croscore fonts have been designed as metrically compatible substitutes for widely used
Microsoft fonts.
Optical sizing During the metal type era, all type was cut in metal and could only be printed at a specific size. It was a natural process to vary a design at different sizes, making it chunkier and clearer to read at smaller sizes. Many digital typefaces are offered with a range of fonts or a variable font axis for different sizes, especially designs sold for professional design use. The art of designing fonts for a specific size is known as
optical sizing. Others will be offered in only one style, but optimized for a specific size. Optical sizes are particularly common for serif fonts, since the fine detail of serif fonts can need to be bulked up for smaller sizes. Typefaces may also be designed differently considering the type of paper on which they will be printed. Designs to be printed on absorbent
newsprint paper are more slender, as the ink naturally spreads as it is absorbed into the paper, and may feature
ink traps—areas left blank into which the ink will soak as it dries. These corrections will not be needed for printing on high-gloss cardboard or display on-screen. Fonts designed for low-resolution displays, meanwhile, may avoid pure circles, fine lines and details a screen cannot render.
Typesetting numbers uses non-lining, or lower-case, figures.|class=skin-invert-image Most typefaces, especially modern designs, include a complementary set of numeric digits. Numbers can be typeset in two main independent sets of ways:
lining and
non-lining figures, and
proportional and
tabular styles. There are a few other styles occasionally used, most notably small-cap figures set uniformly at the height of the small capitals, and "short-ranging figures" slightly lower than cap height. Most modern typefaces set numeric digits by default as lining figures, which are the height of upper-case letters.
Non-lining figures, styled to match lower-case letters, are often common in fonts intended for body text, as they are thought to be less disruptive to the style of running text. They are also called
lower-case numbers or
text figures for the same reason.
Tabular figures The horizontal spacing of digits can also be
proportional, with a character width tightly matching the width of the figure itself, or
tabular, where all digits have the same width. Proportional spacing places the digits closely together, reducing empty space in a document, and is thought to allow the numbers to blend into the text more effectively. As tabular spacing makes all numbers with the same number of digits the same width, it is used for typesetting documents such as price lists, stock listings and sums in mathematics textbooks, all of which require columns of numeric figures to line up on top of each other for easier comparison. Tabular spacing is also a common feature of simple printing devices such as
cash registers and date-stamps. Characters of uniform width are a standard feature of so-called
monospaced fonts, used in programming and on typewriters. However, many fonts that are not monospaced use tabular figures. More complex font designs may include two or more combinations with one as the default and others as alternate characters. Of the four possibilities, non-lining tabular figures are particularly rare since there is no common use for them. Fonts intended for professional use in documents such as business reports may also make the bold-style tabular figures take up the same width as the regular (non-bold) numbers, so a bold-style total would appear just as wide as the same sum in regular style. ==Style of typefaces ==