Quality Printing on the Web
Adobe Systems Incorporated is a company with a more than 10 year history
of providing technology for high quality printing. The Adobe PostScript
langauge has been the standard for high quality page descriptions, both
for computer based printing and for newspaper, publication and commercial
printer. Adobe has been a prime supplier of high quality, scalable fonts
for publishing world wide. With the creation of the Portable Document Format
(PDF) Adobe extended the power and quality of PostScript to displays as
well as printing.
Manager of Standards
Adobe Systems Incorporated
April 23, 1996
There are many issues involved with printing documents available on the
Web. In this statement, I only wish to address two of the major issues:
a media type for resolution independent graphcs and fonts. Adobe Systems
believes HTML and the Portable Document Format (PDF) are complementary.
A good example of the synergistic relationship possible between HTML and
PDF is using PDF for graphical objects within HTML documents. The case for
PDF as a media type for graphics in HTML is presented in the second section
of this paper. Immediately below is Adobe's view of the goals for extensions
to HTML to support a broad range of fonts.
Goals for a Web Font Solution
Rather than attempt to present a solution at this time, I believe that it
is first important to agree upon what the goals of this solution should
be. Much time could be wasted discsussing details if the particpants are
trying to get to different final results. In that view, I present the following
list as a (partial) set of goals that should be satisfied by a Web Font
- [single doc] Support a single document with possibly many fonts used
- [multi doc] Support a collections of documents/pages (both in HTML and
in PDF) that use the same set of fonts. This may be a book, or a subsite
or a collections of sites
- [rapid display] Provide rapid display of the text in a document even
when a number of fonts are involved. (This could involve temporary font
substitutions which are replaced when the real font data arrives. Adobe
calls this progressive rendering. This could involve font subsetting and
- [Ease of Authoring] Creation of documents using Webfonts should be as
easy as creating documents for any other environment.
- [authoring compatability] Document creators will not need to acquire
new sets of fonts for Web documents.
- [Worldwide support] The Webfont technology should support glyphs for
the full Unicode character code repetoire and should be able of supporting
glyphs from any source.
- [Rendering quality] Provide a rendering quality that matchs current
state-of-the-art font rendering (or better) and provides faithful reproduction
of the user's fonts (font fidelity).
- [Better than GIF] The results of type produced with Webfonts and HTML
should be as good as or better than type rendered into GIF files; that is,
designers should not need to create a GIF file just to do good typography.
- [Request only missing data] Request fonts from a server only when the
needed font data is not available local to the browser. (The font data may
be installed on the platform on which the browser is running or the font
data may be cached from some previous (partial) download.)
- [Client controllable] Much like the ability to turn off image retrieval
when displaying HTML files, the user of the browser should be able to turn
off font retreival and the browser will make best possible substitutions
for the referenced fonts.
- [Minimal size] Reduce amount of font data that needs to be transfered
for a given document/page to a small a size as possible.
- [Ease of use] The Webfont technology should not make excessive resource
demands (such as large cache sizes) on the browser platform; it should be
a lightweight solution.
- [IP rights] Protect the IP rights of the font vendors.
- [Time to market] The chosen Webfont technology should be deliverable
within this year.
- [HTML syntax] Define how fonts are referenced from an HTML document.
Where can these font references be placed. How do font references work with
the <FONT> element and CSS-1 Style sheets?
Portable Document Format (PDF): A Media Type for Graphics
HTML is a powerful format for text that requires equally powerful formats
for representing graphical and pictorial information. There is a positive,
synergistic opportunity to combine the graphical representation capability
of the Portable Document Format (PDF) with HTML to represent visually rich
content. HTML provides flexible text; PDF provides powerful graphics.
PDF is an open, publicly available specification
The Portable Document Format (PDF) was developed by Adobe Systems Incorporated
specifically to aid in the exchange and distribution of electronic or digital
documents (or fragments thereof) across a wide range of platforms and
technologies. The PDF representation of a document is independent of application
software, hardware, and operating system used to create that electronic
document. Thus, PDF is intended to provide interchange of already formatted
content, such as graphics, in the same environments in which HTML provides
interchange of revisable, retargetable text.
PDF has been an open, published, publicly available specification from its
original annoucement. Both PDF producers and PDF consumers (viewers or printers)
have been implemented by multiple, independent organizations. The ANSI Committee
on Graphics Arts Technologies Standards (CGATS) has announced the creation
of an ANSI (and likely ISO) standard for interchanging digital pages using
PDF. Thus PDF is a suitable format for Web; it already has a MIME type,
PDF provides visually rich, design controlled content
Controlling the appearance of your documents on the Web is a challenge.
With PDF, however, you can acheive the highest quality and greatest control
to preserve the integrity of your design -- including scalable typefaces
and graphics. PDF is designed to capture the final formatting decisions,
the positioning of elements, and faithfully reproduce them, both when displayed
on a screen and when printed.
Print Ready content
PDF is derived from the well established PostScript (tm) Language. It has
(or will have with the release of the final Adobe Acrobat (tm) Amber products)
the full power of the level 2 PostScript Langauge. Therefore, there is a
straightforward translation from a PDF file into a PostScript file providing
access to both quality computer printers and to reproduction using the
to prepare plates for printing presses. (Acrobat products also are capable
of printing on a range of non-PostScript printers.)
Ease of Authoring
PDF files are easy to create. Your existing tools for document creation
already support the creation of PDF files. For many Windows and MacIntosh
applications, creating a PDF file is as simple as printing the document.
Other applications provide "SaveAs" PDF. For applications that
produce their output in the PostScript Language, there is the Adobe Acrobat
Distiller that converts the PostScript to PDF, compressing it and allowing
image downsampling to further reduce the resulting file size. Finally, for
documents available only in paper form, the so called legacy documents,
there is Adobe Acrobat Capture to do text recognition and to create a PDF
form of the document that looks just like the scanned page. Since text is
represented in a form that allows extracting the character content, these
PDF documents, no matter how created, can also be indexed. In short, if
you can (or did) print it, you can PDF it.
PDF is an object-oriented, device independent representation of the document.
Text is represented as strings that are rendered using high quality, typograhic
scalable fonts. These fonts are identified with enough information to allow
quality substitutions to be performed if the font is not available at the
receiving site or the real font data can be embeded in the font for printing
and viewing. Both European and non-European (Asian) fonts are supported.
The Adobe Acrobat Amber viewers provide anti-aliased display of these fonts.
Graphics are respresented using the time proven PostScript imaging model.
The PDF language has the full capability of PostScript, already used to
represent most sophisticated printed graphics. PDF also has the wide range
of PostScript Level 2 image formats. This includes JPEG and CCITT compression
with accurate, device independent colors. This allows the same image to
be used for display on the screen (by subsampling) and for printing (because
the image data is scaled as needed).
PDF goes beyond PostScript in a number of ways. The most important of these
for the Web is the inclusion of URL (and non-URL) based hyperlinks which
allow PDF files to intimately linked with HTML files and other Web document.
In addition, PDF files can be optimized for rapid page by page display in
a Web browser.
Ease of use
PDF support on the Web is easily available. Adobe provides a free Acrobat
Reader on a number of platforms (Mac's, Windows, a set of Unix platforms,
and more). This reader can be downloaded from www.adobe.com. The reader
is enable to work with standard web browsers to allow display of PDF documents
in the browsers window or within frames within that window. Thus PDF is
a natural format to combine with HTML to handle the graphics/image intensive
or controlled design portions of a document that HTML cannot do.
Summary: HTML plus PDF is more powerful than either alone
HTML was designed to allow optimal formatting for each different presentation
enviroment; for example, different formatting for display windows and print
files. PDF was designed to faithfully capture the result of a formatting
process for both display and printing. PDF was also designed to have the
proven power of the PostScript Language graphics capability.Together, HTML
and PDF allow a document designer to produce document designs that include
powerful graphics and make appropriate trade-offs between flexibility and
design control. Since PDF is device and resolution independent, the same
file can be suitable for both screen display and printing. It is an ideal
choice for a media type to embed in and augment HTML documents.
Adobe, Acrobat and PostScript are trademarks of Adobe Systems Incorporated.