A SIDE FROM the software bundled with Micrsosoft Windows, the most ubiquitous program on computers today may be one you barely notice because it does its job so well.
It's called Adobe Acrobat Reader. Its job is to display and print documents with the exact typefaces, graphics, photos and layout its creator intended, no matter what kind of computer or printer you're using.
If you've used a PC for any length of time, you've probably viewed one of these documents - a user manual, brochure, catalog, form or report - either with Acrobat Reader or with an Acrobat plug-in for your Web browser.
These documents are stored with a PDF file extension, which stands for Adobe's Portable Document Format. It's a standard, compact way of packaging all the information in a document so your computer can recreate it on screen or in print.
Although it's easy to read PDF documents, until recently the software to create them was too expensive for casual users. But today there are a half-dozen programs that will do the job for a relatively small investment - or even for free.
First, a little history. Before the PDF standard existed, there were two ways to transmit a document. One was to print it, duplicate it and deliver it by hand, mail or fax - a tedious and often expensive process.
The other was to e-mail the document in its original form - for example, as a Microsoft Word or Excel spreadsheet file. But that required the recipient to have the same software and typefaces installed on his computer. Nor were transmited documents secure - anyone with the originating program could change them.
Adobe Systems created the PDF system as part of its desktop publishing business, and it's hard to overstate its impact.
The most prolific publisher of PDF documents may be the Internal Revenue Service, which posts 852 government tax forms on its Web site in PDF format. So if it's April 14 and you're desperately in need of Form 4868 (Automatic Extension of Time to File), you can download it, print it and relax.
The system works as well as it does because Adobe gives its reader away. It's available for Windows, Mac, Unix, and handheld computers. Many PC makers bundle it with their machines. If you don't have it, you can download it at www.adobe.com.
So how does Adobe make its money from PDFs? By selling Acrobat, the software that creates them. It's a $250 product, which is a bargain for large business customers who save bundles on paper, toner, stapling, printing fees and labor by creating PDFs and distributing them electronically.
Unfortunately, Acrobat's price tag is a bit stiff for home, small business, school and other occasional users who might apply it to correspondence, flyers, price lists, brochures and newsletters.
But, over the past few years, other publishers have devised simple programs that will create PDFs. They're not as powerful as Acrobat, which makes it easy to combine PDFs, touch up mistakes, set up a bookmarked table of contents with thumbnail previews and create PDF forms that can be filled in on screen.
But the inexpensive alternatives will generate accurate PDF files from most Windows applications, with a minimum of fuss. I tried two of them, RoboPDF and PDF995, and had no complaints about either.
Both install as printer drivers, which means you can select them instead of your regular printer from any Windows print dialog box. Both work best if you have Acrobat Reader installed. When you print a document, the drivers generate PDF files and display them in Reader. You save the files on your hard drive or e-mail them directly.
Of the two, the $49.95 RoboPDF is the more refined product. Its publisher, eHelp Corp., has long been popular with developers who use its software to generate Windows help files.
All of RoboPDF's features are available by selecting the Properties button from a Windows print dialog box. You can adjust image quality versus file size and create a watermark that appears on every page. Security features provide two levels of encryption and password protection that can limit users' ability to print, copy or modify the file.
A downloadable demo version (www.robopdf.com) will produce basic PDFs with an embedded watermark. Registering online removes the watermark and unlocks all the program's features.
PDF995 consists of three programs - a basic PDF generator; an editor that can combine documents, add a watermark, or create boomarks in saved documents; and a security module.
You can download any or all programs and use them free of charge - but an advertising browser window will pop up whenever you print.
To its credit, the publisher doesn't install any insidious spyware or adware on your PC - just a command that pops up a window that displays the company's Web site. To get rid of it, you can register one module for $9.95 or all of them for $19.95.
I tested both programs with Web pages, Word documents, Excel Spreadsheets, databases from Microsoft Access and a page from a high-resolution photo album generated by Hewlett Packard imaging software. Both programs produced files that were virtually identical to PDFs I created using Adobe Acrobat.
Both RoboPDF and PDF995 were faster than Acrobat, particularly with the large photo file. All three produced files of different sizes from the same document. None was consistently more efficent.
PDF995 is the least expensive and offers more features than RoboPDF, but its use of three separate modules - the editor and security program work only on existing files - made it awkward for anything but straight PDF creation.
The bottom line is that both of these inexpensive programs create basic PDF files without much fuss or expense. If you'd like to distribute portable electronic documents, either is worth a try. You'll find them at www.robopdf.com and www.pdf995.com.
For a fling with the real thing, Adobe gives surfers a chance to create a limited number of free PDFs online at createpdf.ado be.com. For other PDF creators and utilities, visit the PDF Zone at www.pdfzone.com.