An Introduction to Type
Since the first recordings of letterforms the concept of the typographic form has evolved into a seemingly endless variety of designs. Type design variations fall within specific categories.
The basic category of type design is the typeface: the specific letterform design of an alphabet, including the serif shape, x-height, length of ascenders and descenders, variation of stroke weight, and any other characteristics that differentiate it from any other design. Each typeface is known by a name, such as Helvetica, Bodoni, and Times Roman, and there may be several interpretations of a typeface such as Century Schoolbook, New Century Schoolbook, and Century Oldstyle. The term typeface, as with much contemporary type terminology, originates with movable type, blocks of wood or metal containing a relief image of a character on one surface, called the face.
A typeface usually includes several design variations called styles. The available number of typestyles, which varies among typefaces, is based on the following visual characteristics:
Character angle. The fundamental typestyles are Roman, the standard vertical style, and italic, which is angled. Italic typestyles are cursive, unique letterform variations based on handwriting, or oblique, angled versions of the Roman style. Cursive italics are usually limited to serif designs.
Character weight. Most typefaces contain bold and bold italic typestyles which are much heavier in stroke weight than the Roman. Many typefaces offer a broader range of weights in addition to Roman, including light and medium (or book) and in addition to bold, including semibold (or demibold), extrabold (or heavy), and black.
Character width. Some typefaces include typestyles with character widths which are narrower than roman, called condensed, and wider, called extended. These typestyles generally include accompanying weight variations.
A collection of all the characters of a typeface in one size and one style is called a font. This includes caps and lowercase, numerals, punctuation marks, and any special characters contained in the typeface, such as symbols or ligatures. The precise meaning of the term font is changing with the times. Originally, a font was a collection of pieces of wood or metal type. They were a specific size and, therefore, could only print one size character. Modern typesetting technology can reproduce almost any size character from one digital font. Therefore, the terms font and typeface, while distinct from one another, are often used interchangeably.
The complete assembly of all the sizes and styles of a typeface forms a type family, bearing the name of its typeface. For example, all the styles and sizes of Helvetica form the Helvetica family. A type family may contain many variations (in fact, the Helvetica family currently contains more than 60 typefaces and styles), but will always retain a strong visual continuity because all of the variations are based on common design characteristics. This allows the designer to present some visual variety on a page while maintaining a strong unified appearance.
The concept of the type family is explored to fullest extent by Sumner Stone in his unique family of typefaces, designed in the 1980s for the contemporary designer using personal computer technology. The Stone family not only contains typeface variations based on a strong design characteristics, but includes complete groups of styles in three different typeface categories. Stone Serif is a traditional thick and thin serif face, Stone Sans is a contemporary uniform strike sans serif face, and Stone Informal is a graceful, contemporary rounded serif typeface. The Stone family was designed, in part to address the new user of typography, that is, the desktop publisher who produces typeset documents without an extensive background in typography and/or design. The Stone family, while running the gamut in typestyle variations, has a strong visual consistency based on common typographic design characteristics. Thus one can more safely combine many different typefaces and styles without worrying about visually incompatible images.
The demands of good design, readability and legibility, especially with large amounts of text, requires attention to the size of type, the length of the typeset line (or column width) and the space between characters, words, lines and paragraphs.
There are three basic units of measurement used in working with type: points, picas, and ems.
Point, pica and inch conversions are as follows:
Points are used to measure height, such as the type size (height of the character) and the space between lines and paragraphs.
The point size of type is the height in points measured from the top of the ascender to the bottom of the descender plus a variable amount of space above and below to keep typeset lines from touching.
Picas are use to measure width, such as the width of a typeset column (length of line) or the space between columns. Picas are more convenient than inches because smaller spaces can be measured in whole units instead of fractions.
Ems and ens
The em space is based on the em quad, which is the square of the type size. For example, the em quad of 48pt. Futura is 48 pts. high by 48 pts. wide. The em space measures 48 points.
It is a particularly useful type measurement because, instead of being static like points and picas, it changes in proportion to the size of type used.
It is primarily used to control space between characters and words, and the space of special characters such as the long dash or em-dash.
The en is half of the em and the width of the en-dash.