OpenType is a file format for scalable (outline) font files that extends the existing TrueType font file format used by Microsoft Windows and Apple Macintosh operating systems. OpenType was developed jointly by Microsoft and Adobe and allows an Adobe PostScript file to be part of a TrueType font file. Prior to OpenType, Adobe did not support TrueType fonts as well it did its own font format, Type 1, for printers that use PostScript. PostScript is an industry standard printer formatting language for higher-quality and more sophisticated printers. OpenType is also known as TrueType Open v. 2.0.
The main advantages of OpenType are:
- Improved cross-platform support
- Better support for the international character sets specified in the Unicode standard
- The ability to specify advanced typographic controls
- Smaller file sizes
- The ability to add a digital signature to a font set to ensure the integrity of the files
The OpenType specification includes a convention for assigning suffixes (file name extensions) to OpenType file names. An OpenType file contains either a TrueType outline font file, which requires a suffix of TTF, or a PostScript outline font file, with a suffix of OTF. A collection of TrueType files packaged together has the suffix TTC.