The students had completed their slide show tracing the dissemination of Islamic art forms through areas of Spain and France in the 11th - 13th centuries. Replete with animated maps and photographic examples, the slide show supported their well-researched spoken narrative on this topic. Now it was time to post the PowerPoint slide show to the class web site.

With the help of their professor, they uploaded the slide show...but it did not make it. The system told them it would take six hours to upload the file! (And so, of course, it would take anyone wishing to view the file the same six hours to download it.) This was not what they were aiming at.

Vignette #2

The kindergartners' beautifully-published books on animal habitats were a big hit at the PTA Curriculum Fair. Printed in full color on glossy paper in a hardback binding, they told the story, in words and pictures, of adaptation, predation, and protection. The students used iPhoto to create the book, based on extensive online research, original photography, group discussion, and serious composition. Now it was time to provide a copy for each student.

But not every family had the iPhoto application on their computer at home, nor did the school have a .Mac account that would have allowed easy uploading and viewing of the book over the Web.

Vignette #3

The three faculty members had worked long and hard to prepare the grant proposal. They each sent their narratives, supporting research papers, and curriculum vitae to the grants manager, all in the form of Microsoft Word documents. As the grants manager compiled the final copy for submission, he noticed that some of the tables looked a little odd, and he remembered seeing a pop-up window warning of some missing fonts. But he'd learned to ignore all those pop-up windows, and so thought nothing of it.

Their proposal was rejected, on the grounds that two crucial data tables were indecipherable to the grant-review committee. The main ideas on the proposal were quite sound, remarked the committee, but the garbled tables did not allow them to see the results of the previous research.

Who are you going to call?

All three of the educators described in these vignettes have problems with their files: they are either too big, too strange, or too messed up to be useful. What they need is the digital equivalent of Ghostbusters, perhaps called Filebusters, to come in and save the day. Most computer-using teachers and students have at one time or another confronted issues such as these, where the files just don't work for the intended educational purpose. And a few have discovered a solution that applies in many similar situations, called Portable Document Format, or PDF.

The PDF format was pioneered by the Adobe company to make it possible to publish a document that would be eminently readable, and nicely printable, no matter what kind of computer you displayed it on, or printer you printed it on, or software you used to view it. And once published by the author, a PDF document could not be altered by the reader. This format was based in part on on Adobe's patented PostScript technology, which is used in many printers and some computer displays.

Here's how PDF could have helped our three disabled digerati:

Had the students of Islamic art saved their slide show in a properly compressed PDF format, it would have been small enough for posting to and downloading from the school web site. That's because the PDF format saves only the information it needs to display the slides on a computer with standard resolution. PowerPoint, on the other hand, saves the full resolution of each image in the slide show, which can amount to many megabytes of unnecessary pixels. And just about everybody has a PDF reader on their computer -- most are free or built in. But not everyone has the latest version of PowerPoint, which must be purchased. So PDF is concise.

Had the kindergartners exported their iPhoto books in PDF format, they could easily have been distributed over the web or on CD, and displayed on any type of computer, with or without iPhoto. From the PDF file, the books could be printed at home, or read directly from the computer screen. In full color. Or emailed to grandma in Texas. PDF is compatible.

Had the faculty members submitted their grant application in PDF format, it would have been much less likely to become contaminated by subsequent reviewers, and much more likely to display exactly as desired no matter what kind of computer or printer was used by the reader. That's because PDF files are not alterable by most grant mangers or reviewers, as Word files are. PDF is consistent.

How to save in PDF

You may need to save your own publications in the PDF format. Here's how:

• On Apple Macintosh, it's easy and built in. No matter which program you are using, choose from the menubar File --> Print. Then, in the Print dialog box, click the PDF button in the lower left corner. You'll get a choice of dispositions: Save as PDF, Compress PDF, and so forth. For the situations described above, Save or Compress would have been the best choices. This process creates a new file on your computer, in PDF format.
   
• On Windows and Linux, you'll need to install a PDF-saving utility on your computer, and then follow its directions to convert your documents to the Portable Document Format. A Google search on PDF utilities for Windows will point you to several free and paid programs for this purpose.

Once saved in PDF format, these files can be distributed by all of the means at your digital disposal:

• You can attach the PDF file to on email, and end it to your correspondents with the confidence that it's concise enough to pass the email file size censor, compatible enough to be read by all, in a consistent format.
   
• You can copy the PDF file to a compact disc, or flash memory stick, and let your public copy them from there to their own computers with the same confidence.