Gallery

Font fundamentals

Posted on 16 Jun 2009 at 00:00

Simon Jones clears up any confusion about font size, leading and kerning, plus discusses what we can expect when office 2010 is finally released.

When you're creating a document, spreadsheet or presentation you get to choose which fonts to use and what size to use them at. Despite this being such a fundamental property of any document, many people seem to be confused by the concept of font size and don't understand why, for instance, a document displayed in Arial 12pt takes up more space than the same document in Calibri 12pt. Let's recap on the basics: font size is measured in "points", and there are 72 of these units to the inch, but font size should more correctly be called "font height", because it only describes the vertical dimension - more specifically, the distance from the bottom of a capital letter on one line to the bottom of a capital on the line below. This allows for the capital height, the height of lower-case descenders (those parts of characters that protrude below the line such as the loop of a "g") and some extra spacing (called "leading" and pronounced "ledding") that stops the letters on adjacent lines from running into each other.

However, the width of individual characters depends on the shape and style of each glyph as it is laid out by the font designer: some fonts have narrow, thin letters that squeeze more words onto each line, while others have round, open letters that make them easier to read. Some fonts have fat letters drawn with thicker strokes for emphasis. Consider, if you will, these three fonts - Arial Narrow, Arial and Wide Latin - which exhibit just those properties. Narrow fonts often contain "compressed", "condensed" or "narrow" in their name, while wider fonts may be called "wide", "extended" or "expanded". You may also come across fonts that are labelled "extra-condensed" or "ultra-wide", which take these properties to more extremes.

Adding an attribute such as Bold or Italic may also change the width of letters in a font - behind the scenes, the application may actually have switched to using a different font (if one is installed) to achieve that attribute. For example, most Windows PCs will have a specific "Arial Bold" font installed that's used whenever a piece of text is in Arial and the user applies the Bold attribute to it. Alternatively, if no such specific bold or italic variant is available, the computer may synthesize a Bold or Italic version on-the-fly from a font outline. Wide Latin, for instance, has no bold or italic variants, but you can still use those attributes in that font and the computer will do its best to mechanically slant all the letters to the right for italic, or increase the width of each stroke to appear bold. Computer synthesized bold or italic fonts aren't as good as properly designed Bold or Italic variants, where a professional font designer has crafted the slopes and swirls of the italics and ensured that the bold glyphs look right.

Not all fonts behave exactly as you would expect and some, particularly older cursive fonts or ones that were designed for foreign alphabets, may be smaller vertically than a modern regular font of the same size. Nevertheless, generally speaking, 12pt is 12pt in any font. You can demonstrate this by using Word 2007's Live Preview feature: if you select a short paragraph, say a line and half, in the middle of a page, pull down the font chooser on the Ribbon and run the cursor up and down the available fonts, you should notice that the text that follows your selected paragraph hardly moves at all. (It may, of course, move if the preview font is so much wider or narrower that the selected text takes up more or fewer lines.)