Software Components

To create the PDF, we use Acrobat Distiller, which ships in a special version bundled with PageMaker or as one element of a stand-alone Acrobat software package. The Distiller program takes the PageMaker output (which is, you recall, just a regular PostScript file), interprets the PostScript, and turns the result into a freestanding Acrobat PDF file. We then upload the PDF to our Web site as we would any other file. Although we design on a Mac and the site runs on Unix, we name the Acrobat file according to PC conventions—eight plus three characters, with ".pdf" as the extension. That allows anyone to download the file without needing to change the name.
And that's it.
Well, not quite. One drawback to Acrobat files is that they can grow quite large if you're not careful. To address this, we also tweak Distiller's settings; although Distiller generally runs fine in default mode. All those fonts and graphics must be squeezed in, as well as the text itself.
We try to limit our Acrobat files to about 300K, which is the most we can expect a typical reader with a modem to download at one time—that takes about two minutes with a 28.8 Kbps modem. This is roughly equivalent to one chapter (or fifty pages) in a novel, including illustrations; we actually present an entire novel in six Acrobat chapters this way.
If you're not using PageMaker, you can buy the Acrobat stand-alone package. It includes several formerly separate programs, including Distiller, Exchange (a PDF editor and annotator), Capture (an optical character recognition system), and Catalog (an indexing utility). Its street price is less than $200. (Capture also comes in a separate, $600 version that supports scanners that have sheet-feeding attachments, like a photocopier, for handling large quantities of documents.)

Tighten Up

You can keep files small through a variety of options in Distiller. The font options alone can be combined in so many ways that in one book a two-page flowchart as complex as the NCAA playoff pairings i is needed to show how each combination of options results in different viewing issues for an end-user. You can include (or "embed") all your fonts in the Acrobat file, but that takes up quite a bit of space, since each style of each font (like Helvetica Oblique) requires 30K to 40K.
If you embed all your fonts, however, the final PDF displays just as you originally intended. If you don't include your fonts, then the PDF will display the same way only if the user viewing the document has those fonts installed on his or her system.
Finally, if you don't embed fonts and the user doesn't have them installed, a version of Adobe Type Manager that's installed along with Acrobat Reader will substitute a generic typeface instead. So the type spacing and sizes are preserved, but the actual font looks quite different. For some purposes, this is okay, but since we're designers, we really want users to see exactly what we've created.
You can get a bit of the best of both worlds by setting Distiller to include only a subset of a font. If you're using a display typeface once for a 12-letter title, for example, subsetting the font can reduce the size of the font file included by as much as 95 percent.
You can also compress graphics. Distiller provides a lot of flexibility—so much that you should test different options before settling on one. You'll also choose different options for different purposes, although Distiller doesn't offer a way to save settings for each of your different output tasks.
Our cover illustration is usually an RGB TIFF file, created at a much higher resolution than needed for viewing or desktop printing, but required for professional high-resolution output. That TIFF file alone could double or triple the size of our Acrobat file. But rather than creating another, smaller version of the TIFF for our PDF file, we instead set Distiller to convert it automatically to 100-dpi medium-compression JPEG format in the Acrobat file. This offers sufficient resolution for viewing and printing for our purposes, and it keeps the size manageable.
Even EPS graphics should be checked for simplicity before handing your layout document over to Distiller. We encountered one large and layered EPS graphic that took up an extraordinary amount of space for its humble purpose. We imported it into Photoshop, saved it as a small TIFF, and let Distiller convert it into an even smaller JPEG for the Acrobat file.
Bear in mind that our approach is to create high-quality printable documents that can be distributed via the Web. Acrobat is perfect for this, but it offers other benefits you may want to explore—starting with the Reader itself.

Web Viewing

The Reader program displays and prints Acrobat files, but it can also display PDFs from within Netscape Navigator and Microsoft Internet Explorer using a browser plug-in that comes with the Acrobat Reader 3.0 package. Make sure your browser isn't running, then copy the plug-in from Acrobat Reader's Web Browser Plug-in folder into Navigator's or Internet Explorer's Plug-ins folder. The next time you run the browser and try to download a PDF, the Reader program will launch, but the PDF will display entirely inside your browser's window.
The potential of viewing PDF files inside a Web browser might lead you to think that you could design an entire Web site using linked PDFs. Adobe recognized this potential early when it re-introduced Acrobat as an alternative to HTML a few years back, and it's been developing some intriguing technology to make it happen.
Luckily, Adobe abandoned its efforts to supplant HTML itself after a few months of trying back in late 1995 and early 1996, and concentrated on making PDF a complement to HTML. The need for the Acrobat plug-in meant that PDF-only sites ran the risk of being dead-ends other than for highly particular projects or audiences that were guaranteed to have and use Acrobat.
To create Web-ready PDFs, start again with your page-layout software, only this time design your pages to fit within a browser window. In recent versions of PageMaker and other Adobe products, you can create links within each page—just like ordinary hypertext, or like mapped graphics where clicking different areas takes you to different locations. You can also use Acrobat Exchange, part of the Acrobat software package, to insert hyperlinks after a PDF file is created.
If you set Distiller to create an "optimized" PDF file, your file will be set up to load efficiently for someone transferring it over the Internet. An optimized PDF stores the text for each page first, then the graphics, and finally the fonts. When you display the file in a browser, the text comes in almost immediately, so you can start reading right away. The larger elements, graphics and fonts, show up shortly thereafter. (This only works with Netscape Navigator, by the way; Internet Explorer supports the plug-in, but must download the entire PDF file before displaying the first page.)

All PDF, All the Time?

Despite our enthusiasm for Acrobat, we're not ready to develop an all-PDF Web site. HTML still has many uses, one of which is to provide Web pages to visitors who don't have Acrobat Reader or the browser plug-in. Marvelous as it is, Acrobat Reader is still an additional program to install, and a multi-megabyte download from Adobe at that. The software is still relatively unfamiliar to the general public, despite Adobe's estimate that 20 million people have either downloaded it or received it bundled with other software. I'm looking forward to the day when I don't have to explain what Acrobat is, or what it can do.
To its credit, Adobe has been working hard to get Acrobat into general distribution—don't forget those online IRS forms. Unlike other software technologies, Acrobat is likely to have a long shelf life given Adobe's position as a leading desktop publishing software company. (Even Quark, maker of QuarkXPress, is trying to build PDF support into their product.)
But I'm still waiting to see the Acrobat disco dancers on television.

Responses

Fall from the High Wire

Ray Davis ([email protected]) writes: "I was disappointed to see the unqualified rave for Adobe's PDF electronic document format. In my experience, Acrobat is far more popular with print-experienced designers who rarely use the Web than it is with Web users.
"For a painful example of PDF overuse, check Adobe's own Web site. The last time I visited, the company was so intent on publicizing its proprietary format that even its press releases (which by definition must be layout independent) were only available in PDF!
"What most print-trained designers don't understand is that the 'lack of precise layout' they complain of in HTML is one of HTML's greatest advantages. By using HTML, your documents can adjust themselves neatly to the viewer's monitor width, monitor resolution, and font choices. You can make text-only information easily available to text-only viewers (or even vision-impaired 'listeners'). And, since computer users are used to vertical scrolling and use of vertical white space, you can divide your content into logical sections rather than into arbitrarily sized pages.
"On the other hand, by using PDF, your documents may become illegible or unavailable. At the very least, they'll cause a break in the viewing experience and their download times will increase. PDF does make sense when precise layout of an entire document is truly required—but such occasions are far rarer on the Web than many print designers seem to believe."

Special Acrobatics

Francois Pottier ([email protected]) writes: "For people who don't want to buy the full Acrobat package, it's also possible to create PDF files using free tools, like a recent version of GhostScript, which can convert PostScript files to PDF files. (I don't know if it allows including hyperlinks, though.) The PostScript file itself can be created with a free tool such as TeX."

This article originally appeared in NetBITS. Posted with permission.