W3C Workshop on High Quality Printing from the Web

MicroType Express:
Lossless Font Compression Technology

A Position Paper Prepared by Agfa Typographic Systems

April, 1996

Content creators and end users viewing documents on the Web both have similar objectives. One wants to present easy to read, high-quality text in Web documents, while the other wants to receive these documents as they were originally designed. To make this a reality, several technology developments must be combined into a single web publishing product. Agfa Typographic Systems believes that font embedding, subsetting and lossless compression are key ingredients to achieve high quality type on the web.

One of the major objections to embedded fonts is the download time required due to their data file size. While embedding of fonts goes a long way toward reaching the web page design goal of maintaining the original look and feel of documents, it can create a large data file that is slow to download. This file size problem can be addressed with character subsetting and lossless compression technologies.

Character subsetting, the embedding of only the characters of a typeface used in a document, begins to address font file size issues. Agfa believes that character subsetting achieves two main goals for web publishing. First, it reduces file sizes, easing and lowering the cost and time of file transmission. Second, when embedding and character subsetting are configured in a read only format, users are presented with a more efficient way to view/print documents while the intellectual rights of font vendors are preserved. Both Microsoft and Netscape have endorsed this approach of font embedding/subsetting with their recent web strategy announcements.

As designers create more sophisticated Web page content, file sizes continue to increase. While embedding and character subsetting move toward alleviating these problems, the addition of lossless compression has a significant impact. Agfa has developed a lossless compression technology, called MicroType Express, for TrueType, Type 1, Latin and Asian fonts, that when used in conjunction with character subsetting, can compress a font to one tenth its original size.

After decompression, there is no loss of font fidelity since the original typeface outline, instructions and Delta Hints are all intact in the font. The resulting bitmap before and after compression is a 100 percent binary match.

Agfa believes that the best font formats for Web Publishing are TrueType and Type 1. TrueType offers superior on-screen quality when properly hinted, while Type 1 is an industry standard in the traditional printing and publishing world and offers an easy migration path to the Web.

It is Agfa's position that content creators and authors should have a license for any fonts that they use to convey and enhance their messages in Web documents. The content author should then embed the fonts (subsetted and compressed) in the Web document. The fonts would then be freely available without a license for reading and printing from the Web document, but not editing by readers of the document. It should be the responsibility of the web authoring tool and browser product vendors to respect and protect the intellectual property rights of the font owners.

MicroType Express

With these requirements in mind, Agfa has announced its MicroType Express lossless font compression technology for web publishing. MicroType Express is a lossless, on-the-fly compression technology for TrueType and Type 1 fonts that helps reduce character file size and ensure character fidelity and quality.

MicroType Expressís lossless compression technology preserves typeface information, including all hint algorithms for high quality on low resolution displays. MicroType Express can be used with any typeface design, including non-Latin and novelty fonts (e.g. Kanji, Chinese, Korean, unique headline fonts and scripts).

MicroType Express can compress standard font sizes an average of 48 percent before utilizing subsetting. By combining MicroType Expressís character subsetting technology, with its lossless compression, TrueType and Type 1 fonts can be compressed by as much as 90%, significantly reducing the time required to transmit an electronic document.

Code size is 65 Kb for the compressor and decompressor modules. Written in industry standard C++, MicroType Express can compress a single font in 3 seconds, and decompress in 0.4 seconds on a 120 MHz, Pentium based platform. MicroType Express is cross platform and available for Windows 3.1, Windows 95, Windows NT, Macintosh and Unix developers.

Fully compatible and complementary of industry Web publishing solutions, MicroType Express is positioned to be a core element of electronic document creation and distribution.

For more information on MicroType Express and Agfa Typographic Systems, please visit our Web page at http://www.Agfahome.com. Tel: (508) 657-0232. Fax: (508) 657-5328.