Typeface
A typeface is a design of letters, numbers and other symbols, to be used in printing or for electronic display. Most typefaces include variations in size, weight, slope, width, and so on. Each of these variations of the typeface is a font.
There are thousands of different typefaces in existence, with new ones being developed constantly.
The profession of designing typefaces is called type design. Designers of typefaces are called type designers and are often employed by type foundries. In desktop publishing, type designers are sometimes also called "font developers" or "font designers." A typographer is someone who uses typefaces to design a page layout.
Every typeface is a collection of glyphs, each of which represents an individual letter, number, punctuation mark, or other symbol. The same glyph may be used for characters from different writing systems, e.g. roman uppercase A looks the same as Cyrillic uppercase А and Greek uppercase alpha. There are typefaces tailored for special applications, such as cartography, astrology or mathematics.
Terminology
In professional typography, the term typeface is not interchangeable with the word font, because the term font has historically been defined as a given alphabet and its associated characters in a single size. For example, 8-point Caslon Italic was one font, and 10-point Caslon Italic was another. Historically, a font came from a type foundry as a set of "sorts", with number of copies of each character included.As the range of typeface designs increased and requirements of publishers broadened over the centuries, fonts of specific weight and stylistic variants—most commonly regular or roman as distinct from italic, as well as condensed—have led to font families, collections of closely related typeface designs that can include hundreds of styles. A typeface family is typically a group of related typefaces which vary only in weight, orientation, width, etc., but not design. For example, Times is a typeface family, whereas Times Roman, Times Italic and Times Bold are individual typefaces making up the Times family. Typeface families typically include several typefaces, though some, such as Helvetica, may consist of dozens of fonts. In traditional typography, a font family is a set of fonts within the same typeface: for example Times Roman 8, Times Roman 10, Times Roman 12, etc. In web typography, the term "font family", as specified using the HTML code, may equate to a "typeface family" or to a very broad category such as sans-serif that encompass many typeface families.
Another way to look at the distinction between a computer font and a typeface is that a computer font is the vessel—e.g. the software—that provides a set of characters with a given appearance, whereas a typeface is the actual design of such characters. Therefore, a given typeface, such as Times, may be rendered by different fonts, such as computer font files created by this or that vendor, a set of metal type characters etc. In the metal type era, a font also meant a specific point size, but with digital scalable outline fonts this distinction is no longer valid, as a single font may be scaled to any size.
The first "extended" font families, which included a wide range of widths and weights in the same general style emerged in the early 1900s, starting with ATF's Cheltenham, with an initial design by Bertram Grosvenor Goodhue, and many additional faces designed by Morris Fuller Benton. Later examples include Futura, Lucida, ITC Officina. Some became superfamilies as a result of revival, such as Linotype Syntax, Linotype Univers; while others have alternate styling designed as compatible replacements of each other, such as Compatil, Generis
Font superfamilies began to emerge when foundries began to include typefaces with significant structural differences, but some design relationship, under the same general family name. Arguably the first superfamily was created when Morris Fuller Benton created Clearface Gothic for ATF in 1910, a sans-serif companion to the existing Clearface. From a typographer's perspective, the "superfamily" designation does not include sets of unrelated typefaces marketed with the same or similar family names. For example, the foundries that market Caslon Antique and Futura Black and Display named them in association with the Caslon and Futura families despite being structurally unrelated to those families. Consequently, typographers do not consider Caslon Antique and Futura Black/Display to be valid members of any Caslon or Futura 'superfamily'.
Additional or supplemental glyphs intended to match a main typeface have been in use for centuries. In some formats they have been marketed as separate fonts. In the early 1990s, the Adobe Systems type group introduced the idea of expert set fonts, which had a standardized set of additional glyphs, including small caps, old style figures, and additional superior letters, fractions and ligatures not found in the main fonts for the typeface. Supplemental fonts have also included alternate letters such as swashes, dingbats, and alternate character sets, complementing the regular fonts under the same family. However, with introduction of font formats such as OpenType, those supplemental glyphs were merged into the main fonts, relying on specific software capabilities to access the alternate glyphs.
Since Apple's and Microsoft's operating systems supported different character sets in the platform related fonts, some foundries used expert fonts in a different way. These fonts included the characters which were missing on either Macintosh or Windows computers, e.g. fractions, ligatures or some accented glyphs. The goal was to deliver the whole character set to the customer regardless of which operating system was used.
Sizing
The size of typefaces and fonts is traditionally measured in points; point has been defined differently at different times, but now the most popular is the Desktop Publishing point of in. When specified in typographic sizes, such as points or kyus, the height of an em-square, an invisible box which is typically a bit larger than the distance from the tallest ascender to the lowest descender, is scaled to equal the specified size. For example, when setting Helvetica at 12 point, the em square defined in the Helvetica font is scaled to 12 points or. Yet no particular element of 12-point Helvetica need measure exactly 12 points.Frequently measurement in non-typographic units—feet, inches, meters—is of the cap-height, the height of the capital letters. Font size is also commonly measured in millimeters and qs—which is a quarter of a millimeter, kyu in romanized Japanese—and inches.
History
Type foundries have cast fonts in lead alloys from the 1450s until the present, although wood served as the material for some large fonts called wood type during the 19th century, particularly in the United States. In the 1890s, the mechanization of typesetting allowed automated casting of fonts on the fly as lines of type in the size and length needed. This was known as continuous casting, and remained profitable and widespread until its demise in the 1970s. The first machine of this type was the Linotype machine, invented by Ottmar Mergenthaler.During a brief transitional period, photographic technology, known as phototypesetting, utilized tiny high-resolution images of individual glyphs on a film strip in the form of a film negative, with the letters as clear areas on an opaque black background. A high-intensity light source behind the film strip projected the image of each glyph through an optical system, which focused the desired letter onto the light-sensitive phototypesetting paper at a specific size and position. This photographic typesetting process permitted optical scaling, allowing designers to produce multiple sizes from a single font, although physical constraints on the reproduction system used still required design changes at different sizes; for example, ink traps and spikes to allow for spread of ink encountered in the printing stage. Manually operated photocomposition systems using fonts on filmstrips allowed fine kerning between letters without the physical effort of manual typesetting, and spawned an enlarged type design industry in the 1960s and 1970s.
By the mid-1970s, all of the major typeface technologies and all their fonts were in use: letterpress; continuous casting machines; phototypositors; computer-controlled phototypesetters; and the earliest digital typesetters—bulky machines with primitive processors and CRT outputs. From the mid-1980s, as digital typography has grown, users have almost universally adopted which has come to primarily refer to a computer file containing scalable outline letterforms in digital font, in one of several common formats. Some typefaces, such as Verdana, are designed primarily for use on computer screens.
Digital type
Digital type became the dominant form of type in the late 1980s and early 1990s. Digital fonts store the image of each character either as a bitmap in a bitmap font, or by mathematical description of lines and curves in an outline font, also called a vector font. Bitmap fonts were more commonly used in the earlier stages of digital type, and are rarely used today. These bitmapped typefaces were first produced by Casady & Greene, Inc. and were also known as Fluent Fonts. Fluent Fonts became mostly obsolete with the creation of downloadable PostScript fonts, and these new fonts are called Fluent Laser Fonts.When an outline font is used, a rasterizing routine in the application software, operating system or printer renders the character outlines, interpreting the vector instructions to decide which pixels should be black and which ones white. Rasterization is straightforward at high resolutions such as those used by laser printers and in high-end publishing systems. For computer screens, where each individual pixel can mean the difference between legible and illegible characters, some digital fonts use hinting algorithms to make readable bitmaps at small sizes.
Digital fonts may also contain data representing the metrics used for composition, including kerning pairs, component creation data for accented characters, glyph substitution rules for Arabic typography and for connecting script faces, and for simple everyday ligatures like "". Common font formats include TrueType, OpenType and PostScript Type 1, while Metafont is still used by TeX and its variants. Applications using these font formats, including the rasterizers, appear in Microsoft and Apple Computer operating systems, Adobe Systems products and those of several other companies. Digital fonts are created with font editors such as FontForge, RoboFont, Glyphs, Fontlab's TypeTool, FontLab Studio, Fontographer, or AsiaFont Studio.