In typography, the body height or point size refers to the height of the space in which a glyph is defined.
Originally, in metal typesetting, the body height or the font (or point) size was defined by the height of the lead cuboid (metal sort) on which the actual font face is moulded. The body height of a metal sort defined the point size, and was usually slightly larger than the distance between the ascender and descender to allow additional space between the lines of text. More space might be achieved by inserting thin long pieces of lead between the lines of text (that is leading ).
In digital fonts, the body is now a virtual, imaginary area, whose height still equals the point size as it did in metal type. [1]
The distance between one baseline and the next is the sum of the body height and the leading, often expressed as "characters per inch vertically" (as in RFC 678) or lines of text per inch (not to be confused with lines per inch, a measure of printed photograph resolution).
Typography is the art and technique of arranging type to make written language legible, readable and appealing when displayed. The arrangement of type involves selecting typefaces, point sizes, line lengths, line spacing, letter spacing, and spaces between pairs of letters. The term typography is also applied to the style, arrangement, and appearance of the letters, numbers, and symbols created by the process. Type design is a closely related craft, sometimes considered part of typography; most typographers do not design typefaces, and some type designers do not consider themselves typographers. Typography also may be used as an ornamental and decorative device, unrelated to the communication of information.
Type design is the art and process of designing typefaces. This involves drawing each letterform using a consistent style. The basic concepts and design variables are described below.
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.
Dots per inch is a measure of spatial printing, video or image scanner dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch (2.54 cm). Similarly, dots per centimetre refers to the number of individual dots that can be placed within a line of 1 centimetre (0.394 in).
In typography, leading is the space between adjacent lines of type; the exact definition varies.
An em is a unit in the field of typography, equal to the currently specified point size. For example, one em in a 16-point typeface is 16 points. Therefore, this unit is the same for all typefaces at a given point size.
In typography, the point is the smallest unit of measure. It is used for measuring font size, leading, and other items on a printed page. The size of the point has varied throughout printing's history. Since the 18th century, the size of a point has been between 0.18 and 0.4 millimeters. Following the advent of desktop publishing in the 1980s and 1990s, digital printing has largely supplanted the letterpress printing and has established the desktop publishing (DTP) point as the de facto standard. The DTP point is defined as 1⁄72 of an inch (1/72 × 25.4 mm ≈ 0.353 mm) and, as with earlier American point sizes, is considered to be 1⁄12 of a pica.
In printing and typography, hot metal typesetting is a technology for typesetting text in letterpress printing. This method injects molten type metal into a mold that has the shape of one or more glyphs. The resulting sorts or slugs are later used to press ink onto paper. Normally the typecasting machine would be controlled by a keyboard or by a paper tape.
Metric typographic units have been devised and proposed several times to overcome the various traditional point systems. After the French Revolution of 1789 one popular proponent of a switch to metric was Didot, who had been able to standardise the continental European typographic measurement a few decades earlier. The conversion did not happen, though. The Didot point was metrically redefined as 1⁄2660 m (≈ 0.376 mm) in 1879 by Berthold.
A computer font is implemented as a digital data file containing a set of graphically related glyphs. A computer font is designed and created using a font editor. A computer font specifically designed for the computer screen, and not for printing, is a screen font.
In typography, the x-height, or corpus size, is the distance between the baseline and the mean line of lowercase letters in a typeface. Typically, this is the height of the letter x in the font, as well as the letters v, w, and z. One of the most important dimensions of a font, x-height defines how high lowercase letters without ascenders are compared to the cap height of uppercase letters.
Letter spacing, character spacing or tracking is an optically consistent typographical adjustment to the space between letters to change the visual density of a line or block of text. Letter spacing is distinct from kerning, which adjusts the spacing of particular pairs of adjacent characters such as "7." which would appear to be badly spaced if left unadjusted, and leading, the spacing between lines.
Type color, or colour, is an element of typography that describes how dense or heavy the text appears on the page. Finding the correct balance of type color and white space can make text more easily readable. The term type color should not be confused with the usual meaning of color, ; instead it has more to do with the blackness or boldness of the text on the page. A bold font weight creates more contrast on the page, therefore creates more emphasis. Using a bold font is therefore one way that type color can be adjusted.
In metal typesetting, a font is a particular size, weight and style of a typeface. Each font is a matched set of type, with a piece for each glyph. A typeface consists of various fonts that share an overall design.
In typography, line length is the width of a block of typeset text, usually measured in units of length like inches or points or in characters per line. A block of text or paragraph has a maximum line length that fits a determined design. If the lines are too short then the text becomes disjointed; if they are too long, the content loses rhythm as the reader searches for the start of each line.
In typesetting, a slug is any of several kinds of piece of lead or other type metal. One kind of slug is a piece of spacing material used to space paragraphs. In the era of commercial typesetting in metal type, they were usually manufactured in strips of 6-point lead. Another kind of slug is a single sort, bearing a single letter or any other symbol. More recently, a slug can be an entire line of Linotype typeset matter, where a single piece of lead has been cast bearing a line of text.
In typography, a column is one or more vertical blocks of content positioned on a page, separated by gutters or rules. Columns are most commonly used to break up large bodies of text that cannot fit in a single block of text on a page. Additionally, columns are used to improve page composition and readability. Newspapers very frequently use complex multi-column layouts to break up different stories and longer bodies of texts within a story. Column can also more generally refer to the vertical delineations created by a typographic grid system which type and image may be positioned. In page layout, the whitespace on the outside of the page are known as margins; the gap between two facing pages is also considered a gutter, since there are columns on both sides.
In typography, a margin is the area between the main content of a page and the page edges. The margin helps to define where a line of text begins and ends. When a page is justified the text is spread out to be flush with the left and right margins. When two pages of content are combined next to each other, the space between the two pages is known as the gutter. The top and bottom margins of a page are also called "head" and "foot", respectively. The term "margin" can also be used to describe the edge of internal content, such as the right or left edge of a column of text.
Typeface anatomy describes the graphic elements that make up letters in a typeface.
Typefaces are born from the struggle between rules and results. Squeezing a square about 1% helps it look more like a square; to appear the same height as a square, a circle must be measurably taller. The two strokes in an X aren't the same thickness, nor are their parallel edges actually parallel; the vertical stems of a lowercase alphabet are thinner than those of its capitals; the ascender on a d isn't the same length as the descender on a p, and so on. For the rational mind, type design can be a maddening game of drawing things differently in order to make them appear the same.
In typography, a quad was a metal spacer used in letterpress typesetting. The term was later adopted as the generic name for two common sizes of spaces in typography, regardless of the form of typesetting used. An em quad is a space that is one em wide; as wide as the height of the font. An en quad is a space that is one en wide: half the width of an em quad.