THE OPENTYPE EXPERIENCE - PART 2
Part two of two
In Part 1 of The OpenType Experience, Thomas Phinney introduced OpenType:
...In
late 1996, Adobe and Microsoft announced that they were trying to end
the font wars by creating a single font format that would allow for the
best features of both Type 1 and TrueType, as well as extending their
capabilities to deal with the limitations of the old formats. The new
format was to be called OpenType.
OpenType takes the table structure of TrueType fonts (making it easily extensible), and adds three things:
- support for PostScript style outlines and hints
- support for advanced typographic features by way of new tables for glyph positioning and substitution
- requiring the font to map Unicode characters to glyphs--a previously optional element of TrueType fonts (see below - Unicode: the universal character encoding).
Part
of the OpenType agreement included licensing the ATM rasterizer code to
Microsoft, and the TrueType rasterizer to Adobe. Adobe also licensed
their code to Apple. As a result, Mac OS X, Windows 2000 and Windows XP
all support all three font formats natively, without needing ATM.
Although Microsoft and Adobe own the OpenType format, it is also
supported to some degree by Apple. The specification is public, and the
companies welcome input from third parties on future development of the
specification.
Typography and language: the OpenType text model
The
text model of OpenType is that applications should store text using the
underlying Unicode characters (see below), and apply formatting to get
at the specific desired glyphs. In addition to the Unicode mapping of
default glyphs, the font has OpenType layout tables which tell it which
glyphs to use when other forms are desired instead, such as small caps
or swashes. These tables also specify which glyphs should turn into
ligatures, or when a script font needs different glyphs for a letter
when it's at the beginning, middle or end of a word, or is a word by
itself.
Having the transformations distinct from the
underlying text enables the magical activities described at the
beginning of this article. For example, when an OpenType savvy
application displays the ffi ligature, it still knows that the
underlying text is an ffi; it is just getting the ligature by means of
formatting it as a ligature, with the substitution happening
automatically. If the user changes to a font that doesn't have the ffi
ligature, the text might change to an f plus and fi ligature, or to the
three separate letters, depending on what's supported in the newly
selected font. It all happens automatically, and the underlying text
doesn't get "broken" by font changes.
All of this is very
nice for Latin-based languages such as Spanish and English, but it's
not essential. However, OpenType or something like it is essential for
proper typesetting of languages that use "complex scripts" such as
Arabic or the Indic languages. Having letters take different forms
based on their position in the word is a basic part of how Arabic
works, for example.
Complex scripts also require that
some glyphs and even ligatures be contextual. That is, a different
glyph or ligature may be required due to the glyph(s) before and/or
after. But once the technology is in place, even Latin fonts can take
advantage of it. Adobe's Caflisch Script Pro and Bickham Script Std
both take great advantage of these capabilities.
OpenType layout features
So
far, we've mentioned in passing a number of OpenType layout features.
There are in fact too many to list and explain them all here, and some
are only relevant to particular non-Latin scripts.
One
interesting thing is that a number of the OpenType layout features are
typographic effects that can be done by scaling, but doing so yields
typographically poor results. For example, scaling down capitals to use
as small capitals creates small cap letters that are too light and thin
compared to the caps and lower case letters. The same problem applies
to ordinals, fractions, superscript and subscript.
Other
OpenType layout features can't be simulated by scaling. Without a
technology like OpenType, one would have to switch to a separate font.
This applies to features such as ligatures, swashes, titling
alternates, and many others.
OpenType support today
So,
OpenType is great in theory. But can people actually use it? What about
compatibility, and the availability of applications and fonts?
Generally,
compatibility has been surprisingly good. The first thing to know is
that using OpenType fonts doesn't require giving up your existing font
library. It's not like GX, which forced you to convert existing fonts
to a new format. In fact, Adobe carefully modified the names of all
their OpenType fonts so they would not conflict with the old Type 1
names. You can use them side-by-side if you wish.
Although
many older applications can't use the advanced features or language
support that can be built into OpenType fonts, people using these
programmes still get the benefits of single-file, cross-platform fonts.
There have been a few compatibility glitches here and there, but most
are easily worked around, or solved by upgrading software to the latest
versions. See the OpenType readme (listed in the Resources) for more
details.
One of the reasons that compatibility has been
so high is that Adobe and Microsoft spent years laying the foundation
for OpenType to work seamlessly. The entire system-level architecture
is designed for backwards compatibility. For example, once it goes
through a system-level printer driver, an OpenType font is
indistinguishable from a Type 1 font (if it has PostScript outlines) or
a TrueType font (if it has TrueType outlines). It is these sorts of
decisions that make OpenType work smoothly in most applications, even
if the software developer had never heard of OpenType when they wrote
their programme. So, while the fonts work, where are the applications
that support their added benefits? Today, applications supporting
OpenType layout features are still in the minority, except for Adobe's
own applications. Microsoft Office for Windows supports considerable
functionality, but only for those languages that require it for basic
typesetting functionality in that language (e.g. Arabic). Adobe
Illustrator, Photoshop and InDesign support many of the features that
are of interest for western and East Asian languages.
Because
it is such an important programme in the design community, I am often
asked about QuarkXPress' support for OpenType. In other press
interviews, Quark has said that they are working on OpenType layout
support. However, QuarkXPress 6 does not yet speak Unicode, let alone
understand advanced OpenType layout features. Because of the complexity
of switching to Unicode, it seems that the earliest one might even hope
for Quark to support OpenType layout would be QuarkXPress 7. In the
meantime, would you care to check out my company's rather spiffy
application, Adobe InDesign?
That leaves us with the
availability of the fonts themselves. Two years ago, there were only a
handful of OpenType fonts, and almost all of them were from Adobe.
Today, there are thousands available from over two dozen companies. The
entire Adobe Type Library of over 2,200 fonts is available in OpenType
format. URW++ has released over 1,000 OpenType fonts. The other large
foundries (besides Adobe) such as Linotype and Agfa Monotype have
publicly said that they believe OpenType is the format of the future,
and that they are developing OpenType fonts. Most of Microsoft's system
fonts, and Apple's Japanese system fonts, are OpenType. Also, several
well-known smaller foundries, such as migr and House Industries, have
released OpenType fonts. All that is just on the Latin side; OpenType
is also being embraced by major type foundries operating in other
scripts, such as Morisawa and FontWorks making Japanese fonts.
However,
although there are many fonts available, just being in the OpenType
format does not mean that a font has extended language support or extra
typographic features. Indeed, only about 1/3 of the OpenType fonts
available from Adobe have significant added features or extended
language support. To examine the features present in an Adobe OpenType
font before purchase, one can use the Adobe Web site to examine the
language support and typographic features of the font.
For
fonts you already have, it is possible to install a Font Properties
Extension from Microsoft that allows users to right-click on a font to
see a much expanded set of properties, which includes language support
and OpenType layout features.
The Future
From
speaking with my colleagues at type conferences around the world, I
know that most people in the font industry now accept that OpenType is
the direction in which the industry is going. The only questions are
when the applications will reach critical mass, and when the big
foundries will convert their type libraries. With the fall 2003
announcement of the Adobe Creative Suite, featuring Unicode and
OpenType support in Illustrator CS, this critical mass may have finally
arrived.
For end users, it's generally not a question of
whether to switch, but when you will start using OpenType alongside
your other fonts. As the number of available OpenType fonts has
recently increased dramatically, the advantages are many and the
limitations are few, it may be sooner than you think.
Unicode: the universal character encoding
Unicode is a platform-independent universal text character encoding scheme for multi-lingual support. In the Unicode standard, each character gets a unique numbered slot, and slots are not re-used. This will eventually eliminate the problem wherein the character code specified on Windows is not the same as that on the Mac OS, so that what's an on one platform becomes something quite different on the other.
Unicode deals with characters rather than
glyphs. That is, it only deals with semantic rather than typographic
distinctions (with a few exceptions for compatibility with existing
standards). As a result, there is no place for things such as small
capitals within Unicode itself; the Unicode standard assumes that such
distinctions will be made elsewhere. Clearly this suggests that
something like OpenType needs to be layered on top of Unicode.
Unicode
is a standard for encoding text, whether internally for an
application's own use in processing, or in files. Thus, there is such a
thing as a "Unicode plain text file." OpenType fonts have a built-in
mapping from Unicode characters to glyphs in the font, for better
cross-platform functionality. Such mapping is optional in TrueType
fonts, and not built into the font at all for Type 1 fonts. Note that
there can only be one default glyph for a given Unicode codepoint; if
other forms are desired, they must be specified by some other means,
such as OpenType layout features.
The Unicode standard is
defined by The Unicode Consortium, an open group whose membership
currently includes Microsoft, Apple, Adobe, IBM, Xerox, HP, and
virtually every other key player in the information industry. It is an
evolving standard, now at version 4, but few changes being made moving
forward will have any effect on most users.
Unicode is
natively supported in Windows NT 4, 2000 and XP, and in Mac OS X.
Besides just switching to a different language keyboard and typing,
each OS offers a means of directly accessing any Unicode character in
any font. On Mac OS X, it's the Character Palette, while on Windows,
it's the Character Map accessory.
However, older
applications must be revised to use Unicode. Among common design
applications today, Adobe InDesign, Photoshop and the newest version of
Illustrator offer significant Unicode support (as do our video
applications, Premiere and After Effects). The Windows version of
Microsoft Office also supports Unicode, but currently the Mac OS
version does not. It is clear that Unicode is where text is going; the
only question is how long it will take all your favourite software to
adopt it.
For more information about OpenType and other formats
OpenType & Font Formats
www.adobe.com/type/opentype
User Guide for OpenType: General information
OpenType Read Me file: All significant known tech issues
Article on font formats: "TrueType, PostScript Type 1 & OpenType: What's the difference?" www.font.to/downloads/TT_PS_OT.pdf
Unicode
IBM intro to Unicode
oss.software.ibm.com/icu/docs/papers/codepages_and_unicode.html
Unicode Consortium
www.unicode.org
About this article
Parts 1 and 2 of this article were previously published in tipoGrafica 62, year XVIII, August, September, 2004, p. 28 to 33. Translated from Spanish by Peggy Jones and Martin Schmoller.
About Thomas Phinney
Thomas Phinney is a frequent conference speaker and occasional writer who is involved in the technical, artistic, historical and business aspects of type, with a special concern for the issues experienced by end users. He has worked in Adobe's type group for six years, currently as fonts programme manager. Phinney has a Master's degree in graphic arts publishing, specializing in typography and design, from the Rochester (NY) Institute of Technology, and a Master's of business administration from the University of California at Berkeley.