Begin site navigation:
End site navigation.
Tactile map. What is a PDF? PDF is an acronym for Portable Document Format, which is a proprietary file format created by Adobe. PDFs can be created from all Adobe products, for example, Adobe Photoshop, Adobe Acrobat, and Adobe PageMaker. PDF conversion tools are also available that integrate with Microsoft Office applications. Additionally, many scanners have the ability to scan images and documents directly to PDF.
For content authors, PDFs offer an advantage over HTML because they can design complicated layouts using any typefaces and graphics, and the end user will generally view the same layout. PDFs are very scalable and flexible - a PDF can be magnified to 1,600 percent, and the text will remain crisp and clear because it is vector-based. PDFs can be opened, read, and printed using a free browser plug-in called Adobe Acrobat Reader, which is available for a variety of operating systems and platforms.
Because they offer so many desirable features, PDFs are ubiquitous on the Web. They are not, however, generally accessible to people with disabilities, particularly people who use screen readers and speech synthesizers. Some common accessibility problems with PDFs include:
When deciding to publish a PDF for the Web, consider whether the PDF is necessary. Many content authors choose PDFs because they are easier than creating a formatted HTML document. They may be familiar with using publishing applications for printed material, and they often have a strong desire to translate the same formatting and style to their Web documents. However, when it comes to accessibility, it is important to remember that excessive formatting unnecessarily complicates your content. The Web is a different medium from print, and content should be designed accordingly.
When a web page requires that an applet, plug-in or other application be present on the client system to interpret page content, the page must provide a link to a plug-in or applet that complies with §1194.21(a) through (l). [Section 508, Part 1194.22, Paragraph (m)]
Creating an accessible PDF is much like creating an accessible Web page. However, because PDFs are proprietary, content authors and developers must learn new and separate techniques for creating properly structured and marked up PDF documents. With complex documents and forms, this can be a very detailed and time-consuming task. Below are some basic steps to follow:
For details on creating accessible PDFs, visit the tutorial links at the end of this document.
PDFs are best used to provide a printable version of lengthy material such as annual reports or guidebooks, large architectural illustrations, and other complex graphical presentations such as maps, charts or PowerPoint slideshows. Try to think in the terms of removing content from presentation. If your information can be recreated easily as part of an HTML document instead, do not publish it as a PDF. This includes simple flyers, brochures, forms, memos, and such. Never include vital information in a PDF file that is not also readily available in HTML format on your Web site.
An accessible PDF begins first with a well-structured document. One of the most common ways to create PDF files is by using the PDFMaker tool available for Microsoft Office applications such as Word. When you use this method, you must properly use Microsoft's structural and formatting options to markup your document, much like you would markup an HTML file.
This means that you must use real headings (not just large, bold fonts), bullets, numbered lists and styles in the original Office document. You must also add alternative text for images and hyperlinks in the Office file in order for the alternative text to be converted into the PDF format.
Example:
A properly structured Word document
(44K Microsoft Word Document)
If you don't properly format your Word document, then the special tags will not be created when the document is converted into PDF. A tagged PDF contains markers to identify different structural elements in the document, much like HTML elements in a Web page. However, these elements are specific to Adobe.
The Adobe Tag dialog box.
Once your document is converted, you can add, edit, or delete tags using Adobe Acrobat. You can also begin with untagged document and add the tags yourself. To learn how to work with Adobe tags, visit the Adobe Accessibility Center link at the bottom of this document. You can confirm the accessibility of your document using Adobe's Accessibility Checker, which will show you if there are structural errors in your PDF.
Example:
The accessible PDF version of the above Word document
(112K PDF)
If no errors are found, the document can generally be considered accessible, as long as the visitors to your Web site are using version 5.0 or later of Adobe Acrobat Reader to view the document.
Enhance the structure of multi-page documents with a table of contents and well-identified section headings. Create bookmarks within your PDF so that users can easily find and go to different sections in the document.
It is better to offer an online form using HTML rather than as a downloadable PDF. The HTML form can be easily and properly marked up so that it is accessible to people with disabilities. However, many people wish to use PDF forms to retain a specified layout. First, ask yourself if that layout is truly necessary, or it is simply a preference?
Most forms started out as paper-based forms designed to be printed, so they are usually formatted to fit an 8.5 inch by 11 inch document. If you must have the user fill out the form and then print it out and sign it so that it can be officially submitted, or held as document on file, then a properly marked up PDF is acceptable. However, remember that your ultimate need is to collect the data from the user. Consider offering a simpler, more accessible online version of the form, rather than automatically choosing a layout that requires complex formatting.
If you are converting a Word document form into a PDF form, the form fields will not automatically become fillable fields. After properly marking up your Office document and converting it, you must use the full version of Adobe Acrobat to re-create the fields in the PDF file. Remember to ensure keyboard access to your field elements, provide labels for your form fields, and also set the correct tab order.
You can confirm the accessibility of your document using Adobe's Accessibility Checker, which will show you if there are structural errors in your PDF. If no errors are found, the document can generally be considered accessible, as long as the visitors to your Web site are using version 6.0 or later of Adobe Acrobat Reader to view the document. It is only with this version that the form element Tooltips, which are similar to the HTML <LABEL> element, can be read by screen readers and speech synthesizers.
If you include a PDF, include a link on the same page to Adobe Acrobat Reader, along with a description of the size and format of the file. For example:
Creating Accessible Adobe PDF Files (4,383K PDF)
Many documents on this page require the free
Adobe Acrobat Reader plug-in for viewing.
Include the name, telephone number and e-mail address of someone who people can contact if they have trouble accessing your PDF, and be prepared to offer the information in another format, if requested.
