There are several classifications of typefaces. Firstly, there
are fixed width fonts, and variable width fonts.
The fixed width fonts look like typewriter text, because
each character is the same width. This quality is desirable for
something like a text editor or a computer console, but not
desirable for the body text of
a long document. The other class is variable
width. Most of the fonts you will use are variable width, though
fixed with can be useful also ( for example, all the example
shell commands in this document are illustrated with a
fixed with font ). The most well known fixed width font
is courier.
To serif or not to serif ?
Serifs are little hooks on the ends of characters. For example, the
letter i in a font such as Times Roman has serifs protruding from
the base of the i and the head of the i.
Serif fonts are usually considered more readable than
fonts without serifs. There are many different types of serif fonts.
Sans serif fonts do not have these little hooks, so they have
a starker appearance. One usually does not write a long book
using a sans serif font for the body text. There are sans serif
fonts that are readable enough to be well suited to documents
that are supposed to be browsed / skimmed ( web pages, catalogues,
marketting brochures ). Another application that sans serif fonts
have is as display fonts on computer screens, especially at
small sizes. The lack of detail in the font can provide it with
more clarity. For example, Microsoft touts Verdana as being
readable at very small sizes on screen.
Notable sans serif fonts include Lucida sans, MS Comic Sans,
Verdana, Myriad, Avant Garde, Arial, Century Gothic and Helvetica.
By the way, Helvetica is considered harmful by typographers.
It is somewhat overused, and many books by typographers plead
users to stay away from it.
The old and the new -- different types of Serif fonts
Old Style
Old style fonts are based on very traditional styles dating as
far back as the late 15th century. Old style fonts tend
to be conservative in design, and very readable. They are well
suited to writing long documents. The name ``old style'' refers
to the style of the font, as opposed to the date of its design.
There are classic old style fonts, such as Goudy Old Style,
which wre designed in the 20th century.
The old style class of fonts has the following distinguishing features:
Well defined, shapely serifs.
Diagonal emphasis. Imagine drawing a font with a fountain pen,
where lines 45 degrees anticlockwise from vertical are heavy
and lines 45 degrees clockwise from verticle are light. Old style
fonts often have this appearance.
Readability. Old style fonts are almost always very readable.
Subtlety and lack of contrast. The old style fonts have heavy
lines and light lines but the contrast in weight is subtle,
not stark.
Notable Old Style fonts include Garamond, Goudy Old Style, Jenson,
and Caslon ( the latter is contentious -- some consider it transitional )
Moderns ( or didone )
The moderns are the opposite of old style fonts. These fonts
typically have more character, and more attitude than their old style
counterparts, and can be used to add character to a document rather
than to typeset a long piece. However, nothing is black and white --
and there are some modern fonts such as computer modern and
Monotype modern, and New Century Schoolbook are very readable
( the contrast between heavy and light is softened to
add readability ).
They are based on the designs popular in the 19th century and
later. Their distinguishing features include:
Lighter serifs, often just thin horizontal lines.
Vertical emphasis. Vertical lines are heavy, horizontal
lines are light.
Many moderns have a stark contrast between light and heavy strokes.
Modern typefaces with high contrast between light and heavy
strokes are not as readable as the old style fonts.
Bodoni is the most notable modern. Other moderns include computer
modern, and Monotype modern ( on which computer modern is based ).
Transitional
Transitional fonts fit somewhere in between moderns and old style fonts.
Many of the transitionals have the same kind of readability as the old
styles. However, they are based on slightly later design. While
a move in the direction of the moderns may be visible in these
fonts, they are still much more subtle than the the moderns.
Examples of transitionals include Times Roman, Utopia, Bulmer,
and Baskerville. Of these, Times leans towards old style, while
Bulmer looks very modern.
Slab Serifs
The slab serif fonts are so named because they have thick, block
like serifs, as opposed to the smooth hooks of the old styles
or the thin lines of some of the moderns.
Slab serif fonts tend to be sturdy looking and are generally quite
readable. Many of the slab serifs have Egyptian names -- such
as Nile, and Egyptienne ( though they are not really in any way Egyptian ).
These fonts are great for producing readable text that may suffer
some dilution in quality ( such as photocpied documents, and documents
printed on newspaper ). These fonts tend to look fairly sturdy.
The most notable slab serif fonts are Clarendon, Memphis and
Egyptienne, as well as several typewriter fonts.
Many of the slab serif fonts are fixed width. Conversely, most
( almost all ) fixed width fonts are slab serif.
The Sans Serif Revolution
Surprisingly, the rise of sans serif fonts is a fairly recent
phenomenon. The first well known sans serif fonts were designed in the
19th early 20th century. The earlier designs include Futura,
Grotesque and Gill Sans. These fonts represent respectively
the ``geometric'', ``grotesque'' and ``humanist'' classes
of sans serif fonts.
Grotesque
The grotesques where so named because the public were initially
somewhat shocked by their relatively stark design. Groteques are
very bare in appearance due to the absence of serifs, and the simpler,
cleaner designs. Because of their ``in your face'' appearance,
grotesques are good for headlines. The more readable variations also
work quite well for comic books, and marketting brochures,
where the body text comes in small doses. Grotesques don't look
as artsy as their geometric counterparts.
Compared to the geometrics, they have more variation in weight, more
strokes, they are squarer ( because they don't use such
circular arcs ). They use a different upper case G and lower case
a to the geometrics.
While they are minimalistic
but don't go to the same extreme as the brutally avant-garde
geometrics.
Notable grotesques include the overused Helvetica, Grotesque,
Arial, Franklin Gothic, and Univers.
Geometric
The Futura font came with the manifesto: form follows function.
The geometric class of fonts has a stark minimalistic appearance.
Distinguishing features include a constant line thickness ( no weight ).
This is particularly conspicuous in the bold variants of a font.
Bold groteques and humanist fonts often show some notable
variation in weight while this rarely happens with the geometric
fonts. Also notable is the precise minimalism of these designs.
The characters almost always are made up from straight horizontal and
vertical lines, and arcs that are very circular ( to the point
where they often look as though they were drawn with a compass ).
The characters have a minimal number
of strokes. This gives them a contemporary look in that they
embrace the minimalistic philosophy that would later take the
world of modern art by storm.
A tell tale sign that a font is a geometric type is the upper case
``G'', which consists of a minimalistic combination of two
strokes -- a long circular arc and a horizontal line.
The other character that stands out is the lower case ``a'' --
which is again two simple strokes, a straight vertical line and
a circle ( the other ``a'' character is more complex which is why
it is not used ).
Notable geometrics include Avant Garde, Futura, and Century
Gothic.
Humanist
As the name might suggest, humanist fonts were designed with a goal
of being less mechanical in appearance. In many ways, they are
more similar to the serif fonts than the geometrics and the
grotesques. They are said to have a ``pen drawn'' look about them.
They tend to have subtle variation in weight, especially observable
in bold variants. The curve shapes are considerably less rigid than
those of the geometrics. Many of them are distinguishable by the
``double story'' lower case g, which is the same shape as the g
used in the old style serif fonts.
The humanist typefaces are the easiest to use without producing an
ugly document as they are relatively compatible with the old style
fonts.
Compatible Typefaces
Grouping typefaces is not easy, so it pays to avoid using too many on
the one page. A logical choice of two typefaces consists of a serif
and a sans serif.
Monotype's Typography 101 page
provides a category-matchup. They conclude that
the moderns and geometrics form good pairs, while
the old styles and humanists also go together well.
The transitionals are also paired with the humanists.
The slab serifs are paired with the grotesques, and
some variants of the slab serifs are also said to match
the geometrics or humanists.
From reading this, one gets the impression that their
philosophy is essentially to match the more conservative
serifs with the more moderate sans serifs, and pair the
wilder modern serifs with the avant garde looking ( pun unavoidable )
geometrics.
Properly spacing fonts brings with it all sorts of issues.
For example, to properly typeset the letters ``fi'', the i should
be very close to the f. The problem is that this causes the dot
on the i to collide with the f, and the serif on the head of the i
to collide with the horizontal stroke of the f.
To deal with this problem, font collections include ligatures.
For example, the ``fi'' ligature character is a single character that
one can substitute for the the two character string ``fi''.
Most fonts contain fi and fl ligatures. Expert fonts discussed
later often include extra ligatures, such as ffl, ffi, and a dotless
i character.
Small caps fonts
Small caps fonts are fonts that have reduced size upper case letters
in place of the lower case letters. These are useful for writing
headings that require emphasis ( and they are often used in LaTeX ).
Typically, when one writes a heading in small caps, they use a large
cap for the beginning of each word, and small capitals for the rest
of the word ( ``title case'' ). The advantage of this over using
all caps is that you get something that is much more readable
( using all caps is a big typographic sin ).
Expert fonts
Expert fonts consist of several extras designed to supplement a typeface.
These include things like ligatures, ornaments ( much like a
mini-dingbats collection designed to go with the typeface ),
small caps fonts, and swash capitals ( fancy, calligraphic letters ).
Font metrics define the spacing between variable width fonts.
The metrics include information about the size of the font,
and kerning information, which assigns kerning
pairs -- pairs of characters that should be given different
spacing. For example, the letters ``To'' would usually belong in
a kerning pair, because correctly spaced ( or kerned ), the o
should partly sit under the T. Typesetting programs such as LaTeX
need to know information about kerning so that they can make decisions
about where to break lines and pages. The same applies to WYWIWYG
publishing programs.
In addition to the metrics, is the font outline, or shape.
The components of the fonts shape ( a stroke, an accent, etc )
are called ``glyphs''.