Font Formats

OpenType
PostScript Type 1
TrueType

OpenType

OpenType™ is a font file format developed by Adobe Systems and Microsoft Corporation. OpenType fonts can have an expanded character set and special layout features for richer linguistic support and advanced typographic control. OpenType fonts use a single file for all of their outline, metric, and bitmap data, making file management simpler. In addition, the same font file works on Macintosh and Windows computers, improving cross-platform portability of documents.
Based on the extensible TrueType® file format, OpenType fonts can support either TrueType or Type 1 ("PostScript®") font data and new typographic layout features. OpenType fonts containing TrueType data may have a .ttf or .ttc suffix in the font file name, while PostScript-based OpenType fonts always have an .otf suffix. The file names for Adobe's OpenType fonts, such as “NuevaStd-Light.otf”, are also more user-friendly and descriptive than most Type 1 or TrueType file names. Finally, OpenType fonts containing Type 1 style outlines do so by using the Compact Font Format (CFF), which makes them much smaller than equivalent Type 1 fonts.
At the heart of OpenType is Unicode, a platform-independent, international multi-byte character encoding that covers virtually all of the world’s languages. As a result, OpenType fonts make multilingual typography easier by allowing multiple language character sets in one font. All Adobe OpenType fonts include the standard range of Latin characters used throughout the western world, and several international characters, including the euro currency (€), “estimated”, and litre symbols.
Adobe OpenType “Pro” fonts add a full range of accented characters to support central, eastern European and Baltic languages, such as Turkish, Polish and Latvian. Some of these fonts also contain Cyrillic and Greek character sets. Adobe also offers a range of Japanese OpenType fonts with expanded character sets. These fonts can be distinguished by the word “Pro,” which is part of the font name and appears in application font menus. OpenType fonts that do not contain this added language support are labeled “Standard,” and are designated by an “Std” suffix in the font menu names.
OpenType fonts may also contain up to 65,535 glyphs. This, combined with their typographic layout features, unleashes exciting capabilities. Many non-standard glyphs, such as oldstyle figures, true small capitals, fractions, swashes, superiors, inferiors, ornaments, titling letters, contextual and stylistic alternates, beginning and ending letterforms and a full range of ligatures may also be included in a single font. In the past, a typical Western PostScript Type 1 font was limited to 256 glyphs, forcing users to install and manage two or more style-related fonts in order to access “expert” or other supplemental characters. OpenType significantly simplifies font management and the publishing workflow by ensuring that all of the required glyphs for a document are contained in one cross-platform font file throughout the workflow.
All Adobe OpenType fonts can be installed and used alongside PostScript Type 1 and TrueType fonts, can be printed to most output devices, and (unless otherwise specified by the creator) can be embedded in PDF files. OpenType fonts are natively supported on Windows 2000, Windows XP and Mac OS X, and are compatible with older operating systems via ATM Light, a free system software component from Adobe. Once installed, almost all applications can work with OpenType fonts. However, applications must support Unicode to take advantage of extended language support (such as that found in "Pro" fonts), and support OpenType layout to take advantage of advanced typographic features found in many OpenType fonts.
For more information about OpenType, visit Adobe's OpenType information page. See particularly our OpenType User Guide.

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PostScript Type 1

Adobe Developed by Adobe Systems and first released in 1985, the PostScript Type 1 font format, along with the PostScript page description language, helped spark the desktop publishing revolution. One of the most popular scalable outline font technologies, Type 1 became the standard for professional publishing and graphic arts because of its reliability and the fact that it is supported by virtually all printers, service bureaus and output houses.
On the Macintosh platform, there are two components to a Type 1 font: a screen font suitcase that contains bitmapped screen fonts in specific point sizes and the font’s metric information and a printer font (also known as an outline font) that is used when printing. The printer font is also used by the operating system to create screen fonts for point sizes that are outside of the sizes contained in the screen font suitcase. (Most Type 1 fonts also ship with a third file, called an Adobe Font Metrics (.AFM) file, a text file that also contains the font’s metrics information. Unless your application specifically requires this file, and few applications do, you can discard this file.)
On Windows, Type 1 fonts consist of a PostScript Font Binary (.PFB) file, plus a corresponding PostScript Font Metrics (.PFM) file. (Some very old Type 1 fonts may ship with a .PFB, .AFM, and .INF file. Installing such fonts will create a .PFM file from the .AFM and .INF files.)
The Unix flavor of Type 1 uses PostScript Font ASCII (.PFA) files, plus .AFM files.
Western Type 1 fonts are considered single-byte fonts and are limited to 256 encoded glyphs. As a result, end users must install separate, supplemental fonts in order to receive multi-lingual support, such as Cyrillic or central European language coverage, or advanced typographic capabilities, such as the use of small capitals, oldstyle figures or swashes.
In 1991, Adobe introduced an extension to the Type 1 format called “multiple masters” (MMs) that allowed end users to create a whole range of high-fidelity font “instances” by interpolating between two master font extremes, such as light and black, along a design axis. Although some MM designs were popular, only a handful of MM typefaces were ever released (fewer than 50), mostly by Adobe. Adobe stopped making new MM fonts in 1999, as part of the transition to OpenType. The OpenType specification does not support MM capabilities.
Though originally proprietary, the Type 1 font specification was publicly released by Adobe in 1991, which allowed other foundries and software tool manufacturers to easily create Type 1 fonts. It is estimated that there are something like 40,000 Type 1 fonts available in the market today from a variety of font foundries, design studios and individuals.
Type 1 fonts are natively supported on Windows 2000, Windows XP and Mac OS X, and are compatible with older operating systems via ATM Light, a free system software component from Adobe. The new Windows Presentation Foundation graphics system in Windows Vista does not support Type 1, although Vista will continue to support Type 1 via previous system calls (GDI).
PostScript Type 1 fonts use a series of mathematical formulas to describe the curves and straight lines of a font's glyphs. A series of “hints,” or instructions, are also added to the font that assist a rasterizer in “drawing” the font on a low-resolution printer or on screen. Type 1 fonts can be printed not only on PostScript printers and imagesetters, but also with non-Postscript printers, such as inkjets, using ATM Light or the native Type 1 rasterizers built into revent versions of Windows and Mac OS.

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TrueType

Created at Apple Computer, TrueType is another scalable outline font technology that is supported by Mac OS, Windows, and many other operating systems. First released by Apple with System 7 in 1991, the technology was subsequently licensed to Microsoft, who introduced TrueType support in the Windows 3.1 operating system. Microsoft and Apple have continued to develop the font technology and ship most of their system fonts in TrueType format with their operating systems.
On the Macintosh platform, classic Mac TrueType fonts are delivered in font suitcases that contain one or more TrueType outline fonts—identified by an “AAA” icon—that correspond to each font weight or style. With OS X, Apple delivers their system TrueType fonts in ".dfont" format, which takes the resource fork of the suitcase and places that information inside the data fork. These fonts can better survive moving across Windows and Unix systems. However, Apple is not encouraging other vendors to use the .dfont approach, so third-party Mac TrueType fonts still come in suitcases.
On Windows, each outline font consists of one file with a “TT” icon that contains all of the font’s outline and metrics information. Each font has a ".ttf" extension, though this may not be visible, depending on system settings. TrueType fonts that conform to the OpenType specification as well may have an ".otf" extension, though this is rare today.
Although TrueType is natively supported on both the Macintosh and Windows platforms, you cannot use classic Mac TrueType fonts on Windows directly, though Mac OS X now supports the use of Windows TrueType font files.
TrueType features an extensible table architecture that allows for additional information to be contained in the font. TrueType also allows for extensive hinting controls that direct the exact placement of pixels on screen when the operating system attempts to draw text. While this extensive hinting language is a plus, few TrueType fonts—outside of the core fonts that ship with the Mac and Windows OSs—fully exploit these hinting capabilities. In 1994, Microsoft released an extension to the TrueType format, called TrueType Open, which was replaced by OpenType in 1996.
While both are scalable outline font formats, TrueType differs from PostScript-based fonts in that it uses different mathematical expressions—quadratic expressions instead of cubic expressions—to represent glyph outlines (the curves of a font’s letterforms). TrueType also employs a different hinting mechanism that puts much of the intelligence for screen drawing and printing to low-resolution printers in the font itself, as opposed to PostScript fonts, which use a simpler hinting model and rely on the intelligence of the font rasterizer.
All Adobe applications support TrueType fonts, and TrueType can be reliably printed to virtually all output devices, including high-end imagesetters that include PostScript Level 2 or higher page description language. TrueType can be used in documents alongside Type 1 fonts, but you should avoid using TrueType and Type 1 versions of fonts with the same name in the same document. TrueType fonts that contain digital signatures for verifying data authenticty are considered OpenType fonts, and are denoted by the black and green OpenType icon.

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� 2002, 2006 Adobe Systems Incorporated and its licensors.
All rights reserved.
Adobe, the Adobe logo, ATM, and PostScript are either registered trademarks or trademarks of Adobe Systems Incorporated in the United States and/or other countries. Apple, Macintosh, Mac OS and TrueType are trademarks of Apple Computer, Inc., registered in the U.S. and other countries. Microsoft, Windows, and OpenType are either registered trademarks or trademarks of Microsoft Corporation in the U.S. and/or other countries. All other trademarks are the property of their respective owners.

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	OpenType PostScript Type 1 TrueType

	OpenType
	OpenType™ is a font file format developed by Adobe Systems and Microsoft Corporation. OpenType fonts can have an expanded character set and special layout features for richer linguistic support and advanced typographic control. OpenType fonts use a single file for all of their outline, metric, and bitmap data, making file management simpler. In addition, the same font file works on Macintosh and Windows computers, improving cross-platform portability of documents. Based on the extensible TrueType® file format, OpenType fonts can support either TrueType or Type 1 ("PostScript®") font data and new typographic layout features. OpenType fonts containing TrueType data may have a .ttf or .ttc suffix in the font file name, while PostScript-based OpenType fonts always have an .otf suffix. The file names for Adobe's OpenType fonts, such as “NuevaStd-Light.otf”, are also more user-friendly and descriptive than most Type 1 or TrueType file names. Finally, OpenType fonts containing Type 1 style outlines do so by using the Compact Font Format (CFF), which makes them much smaller than equivalent Type 1 fonts. At the heart of OpenType is Unicode, a platform-independent, international multi-byte character encoding that covers virtually all of the world’s languages. As a result, OpenType fonts make multilingual typography easier by allowing multiple language character sets in one font. All Adobe OpenType fonts include the standard range of Latin characters used throughout the western world, and several international characters, including the euro currency (€), “estimated”, and litre symbols. Adobe OpenType “Pro” fonts add a full range of accented characters to support central, eastern European and Baltic languages, such as Turkish, Polish and Latvian. Some of these fonts also contain Cyrillic and Greek character sets. Adobe also offers a range of Japanese OpenType fonts with expanded character sets. These fonts can be distinguished by the word “Pro,” which is part of the font name and appears in application font menus. OpenType fonts that do not contain this added language support are labeled “Standard,” and are designated by an “Std” suffix in the font menu names. OpenType fonts may also contain up to 65,535 glyphs. This, combined with their typographic layout features, unleashes exciting capabilities. Many non-standard glyphs, such as oldstyle figures, true small capitals, fractions, swashes, superiors, inferiors, ornaments, titling letters, contextual and stylistic alternates, beginning and ending letterforms and a full range of ligatures may also be included in a single font. In the past, a typical Western PostScript Type 1 font was limited to 256 glyphs, forcing users to install and manage two or more style-related fonts in order to access “expert” or other supplemental characters. OpenType significantly simplifies font management and the publishing workflow by ensuring that all of the required glyphs for a document are contained in one cross-platform font file throughout the workflow. All Adobe OpenType fonts can be installed and used alongside PostScript Type 1 and TrueType fonts, can be printed to most output devices, and (unless otherwise specified by the creator) can be embedded in PDF files. OpenType fonts are natively supported on Windows 2000, Windows XP and Mac OS X, and are compatible with older operating systems via ATM Light, a free system software component from Adobe. Once installed, almost all applications can work with OpenType fonts. However, applications must support Unicode to take advantage of extended language support (such as that found in "Pro" fonts), and support OpenType layout to take advantage of advanced typographic features found in many OpenType fonts. For more information about OpenType, visit Adobe's OpenType information page. See particularly our OpenType User Guide.
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	PostScript Type 1
	Developed by Adobe Systems and first released in 1985, the PostScript Type 1 font format, along with the PostScript page description language, helped spark the desktop publishing revolution. One of the most popular scalable outline font technologies, Type 1 became the standard for professional publishing and graphic arts because of its reliability and the fact that it is supported by virtually all printers, service bureaus and output houses. On the Macintosh platform, there are two components to a Type 1 font: a screen font suitcase that contains bitmapped screen fonts in specific point sizes and the font’s metric information and a printer font (also known as an outline font) that is used when printing. The printer font is also used by the operating system to create screen fonts for point sizes that are outside of the sizes contained in the screen font suitcase. (Most Type 1 fonts also ship with a third file, called an Adobe Font Metrics (.AFM) file, a text file that also contains the font’s metrics information. Unless your application specifically requires this file, and few applications do, you can discard this file.) On Windows, Type 1 fonts consist of a PostScript Font Binary (.PFB) file, plus a corresponding PostScript Font Metrics (.PFM) file. (Some very old Type 1 fonts may ship with a .PFB, .AFM, and .INF file. Installing such fonts will create a .PFM file from the .AFM and .INF files.) The Unix flavor of Type 1 uses PostScript Font ASCII (.PFA) files, plus .AFM files. Western Type 1 fonts are considered single-byte fonts and are limited to 256 encoded glyphs. As a result, end users must install separate, supplemental fonts in order to receive multi-lingual support, such as Cyrillic or central European language coverage, or advanced typographic capabilities, such as the use of small capitals, oldstyle figures or swashes. In 1991, Adobe introduced an extension to the Type 1 format called “multiple masters” (MMs) that allowed end users to create a whole range of high-fidelity font “instances” by interpolating between two master font extremes, such as light and black, along a design axis. Although some MM designs were popular, only a handful of MM typefaces were ever released (fewer than 50), mostly by Adobe. Adobe stopped making new MM fonts in 1999, as part of the transition to OpenType. The OpenType specification does not support MM capabilities. Though originally proprietary, the Type 1 font specification was publicly released by Adobe in 1991, which allowed other foundries and software tool manufacturers to easily create Type 1 fonts. It is estimated that there are something like 40,000 Type 1 fonts available in the market today from a variety of font foundries, design studios and individuals. Type 1 fonts are natively supported on Windows 2000, Windows XP and Mac OS X, and are compatible with older operating systems via ATM Light, a free system software component from Adobe. The new Windows Presentation Foundation graphics system in Windows Vista does not support Type 1, although Vista will continue to support Type 1 via previous system calls (GDI). PostScript Type 1 fonts use a series of mathematical formulas to describe the curves and straight lines of a font's glyphs. A series of “hints,” or instructions, are also added to the font that assist a rasterizer in “drawing” the font on a low-resolution printer or on screen. Type 1 fonts can be printed not only on PostScript printers and imagesetters, but also with non-Postscript printers, such as inkjets, using ATM Light or the native Type 1 rasterizers built into revent versions of Windows and Mac OS.
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	TrueType
	Created at Apple Computer, TrueType is another scalable outline font technology that is supported by Mac OS, Windows, and many other operating systems. First released by Apple with System 7 in 1991, the technology was subsequently licensed to Microsoft, who introduced TrueType support in the Windows 3.1 operating system. Microsoft and Apple have continued to develop the font technology and ship most of their system fonts in TrueType format with their operating systems. On the Macintosh platform, classic Mac TrueType fonts are delivered in font suitcases that contain one or more TrueType outline fonts—identified by an “AAA” icon—that correspond to each font weight or style. With OS X, Apple delivers their system TrueType fonts in ".dfont" format, which takes the resource fork of the suitcase and places that information inside the data fork. These fonts can better survive moving across Windows and Unix systems. However, Apple is not encouraging other vendors to use the .dfont approach, so third-party Mac TrueType fonts still come in suitcases. On Windows, each outline font consists of one file with a “TT” icon that contains all of the font’s outline and metrics information. Each font has a ".ttf" extension, though this may not be visible, depending on system settings. TrueType fonts that conform to the OpenType specification as well may have an ".otf" extension, though this is rare today. Although TrueType is natively supported on both the Macintosh and Windows platforms, you cannot use classic Mac TrueType fonts on Windows directly, though Mac OS X now supports the use of Windows TrueType font files. TrueType features an extensible table architecture that allows for additional information to be contained in the font. TrueType also allows for extensive hinting controls that direct the exact placement of pixels on screen when the operating system attempts to draw text. While this extensive hinting language is a plus, few TrueType fonts—outside of the core fonts that ship with the Mac and Windows OSs—fully exploit these hinting capabilities. In 1994, Microsoft released an extension to the TrueType format, called TrueType Open, which was replaced by OpenType in 1996. While both are scalable outline font formats, TrueType differs from PostScript-based fonts in that it uses different mathematical expressions—quadratic expressions instead of cubic expressions—to represent glyph outlines (the curves of a font’s letterforms). TrueType also employs a different hinting mechanism that puts much of the intelligence for screen drawing and printing to low-resolution printers in the font itself, as opposed to PostScript fonts, which use a simpler hinting model and rely on the intelligence of the font rasterizer. All Adobe applications support TrueType fonts, and TrueType can be reliably printed to virtually all output devices, including high-end imagesetters that include PostScript Level 2 or higher page description language. TrueType can be used in documents alongside Type 1 fonts, but you should avoid using TrueType and Type 1 versions of fonts with the same name in the same document. TrueType fonts that contain digital signatures for verifying data authenticty are considered OpenType fonts, and are denoted by the black and green OpenType icon.
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	� 2002, 2006 Adobe Systems Incorporated and its licensors. All rights reserved. Adobe, the Adobe logo, ATM, and PostScript are either registered trademarks or trademarks of Adobe Systems Incorporated in the United States and/or other countries. Apple, Macintosh, Mac OS and TrueType are trademarks of Apple Computer, Inc., registered in the U.S. and other countries. Microsoft, Windows, and OpenType are either registered trademarks or trademarks of Microsoft Corporation in the U.S. and/or other countries. All other trademarks are the property of their respective owners.