understanding font formats

Intro

Font formats

Mac OS X font installation

Managing fonts

Licensing fonts

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Font formats

Mac OS X, as we've discussed in the past, supports a large number of font formats; more so in fact than any other operating system has before. Underneath the hood everything still boils down to various flavours of PostScript and TrueType, but as well as the tried-and-trusted PostScript Type 1 and Mac-compatible TrueType formats, we can use Windows TrueType fonts, OpenType fonts (which can actually be either TrueType-based or PostScript-based under the hood) and, from OS X 10.2 onwards, Multiple Master PostScript fonts.

There is a great deal of confusion about the different font types, in particular regarding the differences between TrueType and PostScript Type 1 fonts. PostScript typefaces are often seen as being better quality than TrueType, but there's actually no technical validity to this idea. TrueType, which was developed by Apple as part of a challenge to Adobe's PostScript licensing fees over a decade ago, is in some ways more advanced than PostScript, and contains all metric and hinting details - the valuable extras that can make the difference between an average and a great typeface - in the font file itself. However, the format has been used to push countless poorly-built fonts onto the market, and earlier PostScript RIPs tended to have memory problems with those faces. As a result professionals still generally shy away from TrueType faces as a whole. The cheap stuff is still likely to be poorly kerned and hinted, but TrueType fonts from reputable foundries should be every bit as good as PostScript versions.

OpenType fonts are labeled with .otf at the end of the filename. Note that these aren't compatible with Mac OS versions prior to OS X, so before buying OpenType fonts make sure you won't need to use them in Mac OS 9. One major advantage of OpenType is the ability to store many more glyphs than older fonts; up to 64,000 - said to be enough for every character in every language. The way this is used is generally much more specific, with swash capitals, extended ligature sets and other character 'alternates' being built into a single font file rather than packaged up as so-called 'expert set' fonts. Better still, with applications that are written to use OpenType to the full, these character variations; ligatures, special glyphs for the beginning or end of words, lines and sentences, can be applied to text automatically. (This technology was developed by Apple from a previous font technology, QuickDraw GX.) Although not many applications take advantage of OpenType's special powers so far, it is supported to varying degrees in Adobe's InDesign and Photoshop, SoftPress' Freeway and Apple's own TextEdit, among others.

Traditional Macintosh TrueType fonts don't necessarily have a filename extension, but newer examples and those from Windows-based sources will have .ttf (TrueType Font) tagged onto the filename. OS X and Windows TrueType fonts are slightly different to those from OS 9 and earlier, and can't be used in older Mac OS versions.

Multiple Master is a form of PostScript font which allows variation of one or more font design parameters, such as weight, to produce custom styles (called instances) from any point between the design extremes. From OS X 10.2 Multiple Master fonts are supported, but so far it doesn't provide a way to create new instances.

What's definitely lost in OS X is support for traditional bitmap-only font resources; fonts in OS X must be outline-based in some way, so fonts without outline components are unfortunately not usable. There is a way around this, but it involves working with full-scale font creation packages. See Bitmap Resurrection for details.

Recognising formats

As Mac OS X handles numerous different kinds of fonts it can be a bit tricky knowing which ones are what. However, there are ways to recognise the different formats whether they are modern or older Mac files or even ones from Windows collections. If the files don't match up to one of these then it's very likely that it either isn't actually a font or it is something that OS X can't yet handle.

• OS X TrueType font names will end with .ttf (TrueType Font).

• Windows TrueType font file names end with .ttf or .ttc; the latter stands for TrueType Collection. Collections are simply multiple fonts stored within single suitcase-like files.

• OpenType font names end with .otf, which is, logically enough, short for OpenType Font.

• Older Mac fonts won't generally use filename extensions. Font files are usually found within suitcase items, and will either show a single letter A or a repeating set of A characters in the icon. The former is the bitmap half of a PostScript font (the other half will have a truncated version of this file's name) and the latter is a complete TrueType font.

• PostScript Type 1 outline font files will have names which are abbreviated versions of the bitmap face files they link with, using the first five characters of the first word then the first three from each following one. For example, the PostScript file for Helvetica Bold Condensed will be called HelveBolCon.