A
font is essentially the design
for a set of characters. It's the combination of typeface and
design characteristics such as size, pitch and spacing. The height of
characters in a font is measured in
points, each point being
approximately 1/72 inch. The width is measured by
pitch, which
refers to how many
characters can fit in an inch. Common pitch
values are 10 and 12. A font is said to be
fixed pitch if every
character has the same width (this type of font is also called monospace). If the widths vary depending on the
shape of the character, it is called a
proportional font.
Font Families
A font
family is a group of fonts that have similarities in design.
One member of the font family may be
bold,
while another member of the same family may be
italic (these characteristics are also referred to as font style).
Families are generally grouped into categories based on design
specifications such as
serifs,
fonts that resemble handwriting, or even its proportional spacing.
The five generic font families consist of fonts in the categories of
serif,
sans-serif,
cursive, fantasy and
monospace.
There are other font families such as Times, Script, Arial and
Courier to name but a few of the more popular families.
Typeface vs. Font
The term font is often used as a synonym for
typeface, which is not
technically correct. For example, some may refer to Times
Roman as
a font, but it is actually a typeface that defines the shape
of each character. Within the Times Roman typeface there are many
fonts to choose from — different sizes and styles (e.g., italic, bold and so
on).
Today many people use the word font to
generally refer to the
computer files saved (or stored) on our
computers, which is why the synonymous use of the two terms exists
today. If you have the Times New Roman typeface installed on your
computer, then you can
make it most any size — from tiny to huge, italic or bold.
Where the terms font and typeface, by definition, mean two different
things, the capability to manipulate a typeface so easily on the
computer means the two terms are often used as interchangeable terms now.
When referring to printing and document creation on a computer at
home or in the office this typically isn't an issue
When working with a
printer or
service bureau, however, the difference between the two terms become relevant. In that scenario, you cannot simply
make Times Roman bold by selecting bold in the Style menu of your graphics or publishing application. To properly output your file to a high-resultion device such as an imagesetter, you need to provide your vendor a Times Roman Bold printer font. It is
in this area of the printing industry where the term typeface and
font do mean two different things and the word font is not able to
be used as a synonym for typeface.
Bit-Mapped & Vector Graphics
System Fonts
Computers and devices use two methods to represent fonts.
One is a
bit-mapped font
where every character is represented by an arrangement of
dots. To print a bit-mapped character, a
printer simply locates the
character's bit-mapped representation stored in
memory and prints
the corresponding dots. Each different font, even when the typeface
is the same, requires a different set of bit-maps.
The second method uses a
vector graphics system to define fonts.
In vector graphics systems, the shape or outline of each character
is defined geometrically. The typeface can be displayed in any size,
so a single font description really represents innumerable fonts.
For this reason, vector fonts are called
scalable fonts
as they can be scaled to any size.
A scalable font is really one font in which the outlines of each character are
geometrically defined. The most popular languages for defining
scaleable fonts are PostScript and TrueType.
The most widely used
scalable-font systems are
PostScript and
TrueType.
PostScript
- A Webopedia
Definition
PostScript is primarily a
language
for printing
documents on
laser printers, but it can be adapted to produce images on
other types of devices. PostScript is the standard for
desktop publishing because it is supported by
imagesetters, the very
high-resolution printers used by
service bureaus to produce camera-ready copy, film and plates for offset printing.
PostScript is an object-oriented
language, meaning that it treats images, including fonts, as
collections of geometrical
objects
rather than as
bit maps.
PostScript fonts are called
outline fonts because the outline of each character is
defined. They are also called
scalable fonts because their size can be changed with
PostScript commands. Given a single typeface definition, a
PostScript printer can thus produce a multitude of fonts. In
contrast, many non-PostScript printers represent fonts with bit
maps. To print a bit-mapped typeface with different sizes, these
printers require a complete set of bit maps for each size.
TrueType
-A
Webopedia Definition
An
outline font technology developed jointly by
Microsoft and
Apple. Because TrueType
support
is built into all
Windows
and
Macintosh
operating systems, anyone using these operating systems can
create
documents using TrueType
fonts.
Since being introduced in 1991, TrueType has quickly become the
dominant font technology for everyday use.
An
outline
font is scalable because, given a geometrical description of a
typeface, a printer or other display device can generate the
characters at any size. What differentiates a scalable font from an
outline font (aside from offering innumerable sizes of each font) is
that
outline fonts have the added advantage that they make the most of an
output device's resolution. The more resolution a printer or
monitor offers, the better an outline font will look.
Aside from the scalability of vector fonts, their other main
advantage over bit-mapped fonts is that they make the most of
high-resolution devices. Bit-mapped fonts look almost the same
whether printed on a 300-dpi printer or a 1,200-dpi printer. In
contrast, vector
fonts look better at a higher the resolution.
Screen Fonts
Despite the advantages of vector fonts, bit-mapped fonts are still
widely used. One reason for this is that small vector fonts do not
look very good on low-resolution devices, such as display monitors
(which are low-resolution when compared with laser printers). Many
computer systems, therefore, use bit-mapped fonts for screen
displays. These are sometimes called screen fonts. A screen
font basically resembles the font for a document, so that what you
see on the screen will look very similar to the end-result (printed
document).
With vector fonts seem to offer more
benefits, some
professionals still prefer to use bit-mapped fonts on high-resolution
printers because characters can be individually tailored to the
printing device. An additional drawback of vector fonts is that
every character must be generated as it is needed. This is a
computation-intensive process that requires a powerful
microprocessor to make it acceptably fast.
