Postscript Type 1: High-End
PostScript fonts remain the preferred font format for high-resolution commercial print output. Why? The vast majority of print high-resolution output devices relies on PostScript raster image processors (RIPs), and has for the last 20 years. Add to it the fact that you can embed any PostScript font in a PDF, and you get an established workflow with consistent quality and predictable results.
TrueType: It's Everywhere
While TrueType is a popular font format for both Windows and Macintosh, it can be unpredictable when used for output to older PostScript Level 1 or 2 imaging systems at higher resolutions. With modern output devices, however, it is hardly ever a problem to rely on TrueType fonts.
Datafork: New for OS X, But Is It Improved?
Macintosh OS X comes with a new file format called a Datafork font; it has the .dfont extension. This is a version of Mac TrueType that has the data and resource forks combined into a new file format. Mac OS X, like Windows, uses extensions to define the file type, eliminating the Mac OS 9 Resource Fork file component, and making Mac OS X files compatible with other OS file systems. If you want to use TrueType, just find Windows .ttf fonts; they work on OS X! Use Apple's DataFork fonts just for OS X display, not print documents.
OpenType: Big Bang, But Worth The Buck?
OpenType, jointly developed by Microsoft and Adobe, is a cross-platform font file format with some great functionality. There are two main benefits of OpenType. First, this font file format offers cross-platform compatibility (the same font files can be installed on Mac OS 9, OS X and Microsoft Windows). That's great when your print service provider could be working on a different platform than your graphic designer.
Second, each OpenType font supports a significant expansion in built-in character sets and attributes — as long as you are using one of the few applications (mostly from Adobe) that support these extended sets. One OpenType font can support fractions, ligatures, ordinals, old-style and dingbat-style characters. These character alternatives are accessed via a fly-out menu from the character palette of your Adobe applications.
The OpenType format supports both TrueType and PostScript font data structures, and can be installed along with PostScript Type 1 and TrueType fonts.
POSTSCRIPT TYPE 1 [MACINTOSH]
Mac Type 1 fonts have two components: the screen font, which is also known as the bitmap font, and the printer font, also known as the outline font. A font suitcase is a special type of folder that can hold multiple screen fonts, but the corresponding printer fonts are always individual files. Font suitcase icons in OS 9 look like a suitcase; in OS X, they have an icon with "FFIL" on them. Outline fonts, also known as printer fonts, carry the font foundry's icon. Both OS X and OS 9/Classic require you to keep a font's screen and printer font pairs in the same folder.
POSTSCRIPT TYPE 1 [WINDOWS]
Windows PostScript fonts have a .pfb extension. Unlike the Mac, Windows PostScript fonts have both the display and printer font information in this one file. This is the only major PC font format that cannot be used with Mac OS X.
OPENTYPE WITH POSTSCRIPT FONT DATA
Microsoft and Adobe jointly developed OpenType to provide a single, cross-platform font format that is flexible enough to meet a variety of needs. OpenType supports font data in both the PostScript and the TrueType format. An OpenType font containing PostScript font data has an .otf extension and works on both the Windows and Mac platforms. Great in theory, but we've experienced problems with .otf fonts when used with Quark 6.x for Mac. The type disappears when the Quark file is converted to PDF. Beware.
OPENTYPE WITH TRUETYPE FONT DATA
An OpenType font with embedded TrueType font data has a .ttf extension, the same as a Windows TrueType font.
Mac TrueType fonts are packaged in suitcases, like the screen font component of a Mac PostScript Type 1 font. Unlike Type 1 fonts, the outline fonts are part of that single font file. Both PostScript suitcase and Mac TrueType suitcase files display the same FFIL icon in Mac OS X, making it difficult to distinguish one from another.
Though Apple invented TrueType, it was Microsoft that made it the most popular font format. With OS X, you can now install Windows TrueType fonts on a Mac, giving Mac users access to thousands of free or low cost .ttf fonts. Beware of quality issues with free fonts, especially kerning and ability to print. If you use .ttf fonts in your document, make sure you can print the file to a desktop printer and/or convert it to a PDF. If it won't print on your laser or ink jet printer, chances are it won't print to our platesetter. Finally, while TrueType fonts from major font foundries should be "embeddable" in a PDF, obscure TrueType fonts may carry a "Do Not Embed" restriction. This is a restriction that is set by the designer of the typeface and will result in font substitution if you try to embed such a font into a PDF document. If you use Adobe Distiller, it will warn you if embedding is not allowed.
TRUETYPE [MAC OS X DATA FORK]
Apple introduced a new variant of TrueType with OS X. It has an extension of .dfont and is the format used for most pre-installed system fonts. You should avoid using this format in your print layouts; be especially carefully with the dfont version of Helvetica Neue, which comes installed with OS X. Use the PostScript or TrueType version of Helvetica Neue if you can.