More basics of typography

Fonts are measured in points, the smallest unit of printing measurement. There are 12 points to a pica, and six picas to an inch, so there are 72 points to an inch. Measuring font size actually comes from measuring the height of the wooden slug, which held the letter. These slugs came in various point sizes—9,10, 12, 14, 18, 24, 30, 36, 48, 60, 72—and those same sizes are common today. There are some common terms when dealing with point size. The x-height is the height of a lowercase letter (such as the x), the ascender is part of the letter that extends above the body of type (like the h) and the descender is the part of the letter that extends below the body of type (such as the g). Type height is measured from the bottom of a descender to the top of an ascender (Harrower 20). While these measurements stated above are absolute, there are also relative measurements, which means they vary from font to font. Examples of relative measurements are em spaces, en spaces, and thin spaces. An em space is a space equal in width to the size of the font, an en space is half an em, and a thin space is a quarter of an em. For example, in 12-point type, an em space is 12 points, an en space is 6 points, and a thin space is 3 points (Binns 14).



The vertical space between lines of type is called leading. It gets this name because way back when type was set by hand, printers added strips of lead below the wooden blocks with letters to add space between lines of type. More specifically, leading is the space from the baseline of one line of text to another. If you add more space between the lines you are loosening the leading, and if you decrease space you are tightening. The horizontal space between letters in a block of text is called tracking. Sometimes this word is confused with kerning, which is the reduction of space between two letters. Loose tracking would be adding space between letters and tight tracking would reduce space (Harrower 21). Click here for more on these terms.

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