Adobe Acrobat performs a high-wire graphics act


While most new software on display at the recent PC Expo computer show in New York consisted of improvements to established programs, one fresh face stood out. Adobe Acrobat, which is just reaching retail stores, is an innovative and impressive technical achievement. It promises to add a dimension to the way people communicate over computer networks.

Acrobat, created by Adobe Systems Inc. of Mountain View, Calif., allows Macintosh and Windows computers to exchange fully formatted documents over networks, including electronic mail systems and by modem, regardless of what applications and fonts are on the receiving machine.

In other words, it breaks down the barriers that have kept people from seeing on one computer screen a complex document that was created on a different computer.

While Acrobat seems to be fairly simple to use once it is installed, it is by no means a simple application. The program involves components called Acrobat Exchange (list price $195), Acrobat Reader ($2,500 for up to 50 users on a network) and Personal Distiller ($695).

A network version of the distiller costs $2,495. These prices are in line with other strategic, networked applications, and Acrobat has the potential to pay for itself rather quickly by eliminating the need to print paper documents or send documents by express courier, or even regular mail.

Electronic publishing

Working together, the various components of Acrobat can transform a complex document -- text, headlines, graphics and photos, much like this newspaper page -- into a new type of computer file that is not dependent on any one kind of computer, operating system or software application.

In real life, this means that a computer user on the network could view this newspaper, or an annual report, or an entire magazine for that matter, on his or her computer screen almost exactly as it appears on paper. It doesn't make any difference that the viewer's computer may not have the same type fonts installed or the same page layout program installed.

Many companies have complex documents that must be published and distributed to employees or key customers -- price lists, telephone directories, annual reports and so on. When these documents are revised, reprinted and redistributed, the cost is significant.

With Acrobat, the documents can be placed on a central computer and distributed electronically, as needed, to recipients.

The document will appear virtually identical to the original regardless of whether it is viewed on a Macintosh on the receptionist's desk or a Windows-based Pentium workstation in the engineering lab. And more barriers will fall later this year when Adobe Systems releases versions of Acrobat for DOS and Unix computers.

The "reading" part of Acrobat is limited to viewing only, which means the text in the image cannot be edited, any more than a facsimile document can be edited. This is a significant drawback of Acrobat, but only, of course, for people who want to edit.

To compensate, Acrobat Exchange allows the reader to annotate the image with electronic "sticky notes." It also has powerful navigational tools to allow readers to move through multipage documents and mark pages for quick reference.

Perhaps the best way to describe Acrobat's strength is to examine the weakness of current ways of exchanging documents.

It is hard enough to send a simple text file, like a business letter, from a Windows computer to a Macintosh, or vice versa. The two computers use different file formats, which is the computer equivalent of one speaking English and the other Cantonese.

It's not exactly a picnic to send a file even between like computers if they don't have the same system resources.

The safest but dullest way to communicate is to break the information down into a primitive computer dialect called ASCII (pronounced ASK-ee), which reduces the information to basic text and number characters.

Communicating in ASCII eliminates the richness of document formatting, including the use of different type fonts and graphics and page layouts. Most electronic mail messages are transmitted in this format.

It is certainly possible to send the text of this column, for example, to someone else on a network , but headlines and other large type, the width of the columns, illustrations, photographs and other embellishments are added on a different computer.

The completed page, now a complex document, is then published by printing it on newsprint. If the writer wished to see the page as a finished product, it would have to be on paper, either the newspaper itself or a facsimile transmission.

The editor could send the file back to the writer electronically, but it would have to revert to straight text form, with no formatting. Forget the illustration, which must either be sent separately as a graphics file or faxed.

Amazing gymnastics

Then consider Acrobat. It can "distill" the image of the completed page into a new file format it calls PDF, for portable document format, which can then be viewed on any computer that has Acrobat Reader software.

To be distilled, the original file must be in the Adobe Postscript format. Postscript, another Adobe technology for describing how a page will look when it is printed or displayed on screen, has become the de facto standard for documents used by publishers and graphic artists.

In distilling the file, Acrobat performs amazing digital gymnastics. It grabs the information about a given type font, but not the font itself. When the document is viewed on someone else's computer, the font is re-created, even if that particular font is not loaded in the receiving computer.

At least, that's the way it works in theory. In practice, the real and ersatz fonts appear to match very closely -- but not exactly. But the difference is not enough to cause the formatting or layout to deconstruct, so headlines and text still fit in their appropriate spaces.

This is impressive, because most computers try to substitute some other type font when an exact match is not available. Lines do not fit, crisp page designs dissolve into chaos, and everything gets ugly in a hurry.

The PDF file is also compressed, meaning that it takes up far less space in memory than it would without compression.

In a demonstration, Adobe showed 110 pages of a popular computer magazine, including full-color photographs and charts, compressed into just a few megabytes. Moving from page 1 to page 110 was as easy and fast as a mouse click.

The Exchange program allows the contents to be shown in thumbnail, or miniaturized, views. Acrobat has a variety of tools that make it easy to telescopically zoom from thumbnail to page view to focus on the smallest detail of a photo, or the fine print on a legal document.

Even the resolution of the viewing computer's display becomes irrelevant. In some cases, Acrobat files look better on another computer screen than they do on the original.

Yet if the technology underlying all these features is impressive, there are some blemishes. First, not everybody is attached to a network or a phone line, so paper publishing is still necessary.

Second, because it works only with Postscript documents, there is a restriction on what kind of files Acrobat can use.

Third, the lack of a built-in text recognition engine, the kind that can convert the image of text into text that can be edited by a computer, is frustrating. The safeguards for document security and access could be stronger. And someday it would be nice to be able to include sound and video components with the documents.

But given Adobe's achievements, those caveats are quibbles.

(Peter Lewis works out of the New York Times' Austin, Texas, bureau: [512] 328-8258.)

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