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Using PDF Files

Portable Document Format (PDF) is a unique document format developed by the Adobe Corporation in an attempt to create a format that combines the best benefits of Web coding, including cross-platform use, small file size, and easy searchability with the best features of traditional print documents, including precise, unchanging formatting; easy printing; and random access (users can easily jump from page 1 to page 7). Because PDFs are encoded with the PostScript printer language, they are readable in virtually any operating system, including Windows, Mac, Linux, and FreeBSD, as long as users have the free Acrobat Reader software (available from www.adobe.com). See the figure below for an example of a PDF in use; when displayed, PDF documents look precisely like their print companions.

PDFs are very widely used, particularly as a means for moving print documents onto the Web; the process for converting a print document to PDF is generally much less difficult than the process for converting it into HTML for normal Web browser display. Before you jump into producing content in PDF, however, consider the following:

When Should I Use PDFs?

PDFs are most appropriate in the following situations:

  1. Print conversion. PDFs are appropriate when used to produce documents that are primarily produced for print but are not easily converted into, or displayed in, HTML. For example, organizations frequently use PDFs for documents like annual reports or journal articles—where the primary means of distribution is print, and the documents are produced in print-friendly software like PageMaker—but they wish to make copies available online for the general public.
  2. Precision matters. PDFs are appropriate when used to produce documents for which precise printing and/or display of the document matters. For example, many organizations use PDFs to produce forms and applications they wish users to print and mail in, because by using PDF they can guarantee that the form will look and print the same on all platforms.
  3. Security matters. PDFs are appropriate when used to produce documents that need to be secure in some way, because PDF files can be locked to prevent editing. For example, organizations use PDFs to secure financial documents and other critical information; it’s possible to lock PDFs so that users cannot copy text or graphics, make changes, or print a document.

When Should I Not Use PDFs?

Don’t use PDFs when HTML is possible and will do the job. PDFs are great for the purposes listed above, but they also impose restrictions on your users because they require specialized software. Users must have machines capable of displaying PDF files and they must also either have PDF-reader software installed or know how to install it themselves. In addition, PDFs don’t allow users as many display options; in HTML, for example, disabled users can use a self-defined style sheet to optimize display for their personal needs, but PDFs adapt less flexibly. If you feel you must use a PDF, consider including the same content in other formats (text file, HTML, etc.) to give your users options.

How Do I Create PDFs?

With the proper software, you can create PDF documents from any program that can print, and Adobe has arranged the licensing of its PDF technology so that developers are free to produce their own PDF-creation and editing software. Adobe’s product for creating and viewing PDFs is Adobe Acrobat, which is available from its Web site and generally discounted for students and educators. But you can also download freeware and shareware PDF-creation tools at shareware sites like www.download.com or from PDF-specific sites like www.pdfzone.com.

Because PDFs are fundamentally encoded in the PostScript printer language—although some programs do allow the option to "Save As…" a PDF file—PDF creation is really a printing process. As a result, most PDF creators work by installing themselves as printers on your system. For example, if you were using Adobe’s Distiller software (included with Acrobat) to create PDFs, you could create a PDF within any application by doing the following:

  1. Select File --> Print.
  2. Select "Acrobat Distiller" from the drop-down "Name" box (see figure below).

  3. Click "OK" to print the file/create the PDF. You will be prompted to select the location where you’d like to save the PDF.

 You are then free to upload or e-mail your PDF; it will be instantly readable to anyone who has Acrobat Reader software.