Web Accessibility, Part 2: Making PDF Files Accessible
I'm always amazed by technology. It grows by leaps and bounds, and seems to take on a life of its own, extending its reach to places we never thought possible.
Technology has provided many opportunities for visually disabled people to enjoy the same Internet content that we all benefit from, just in a different way.
For instance, screen enlargers provide a larger-than-life view of the Internet world, enabling those with low vision to view on screen information at up to 14 times larger. On the other hand, screen readers enable people with no vision to "listen" to onscreen content via synthesized speech output through computer speakers.
Although each of these adaptive technologies comes with its own set of challenges, one great challenge is encountering PDF files that are not created with accessibility in mind. In this case, the technology is useless because the PDF content is either difficult or impossible to access.
For a better glimpse inside the world of adaptive technology, see the first article in this three-part series: "What's All This Talk About Web Accessibility? Part 1: Inside Adaptive Technology."
Fortunately, Adobe has taken the initiative to provide the necessary tools in Acrobat 5 to create accessible PDF files. You can effectively use these tools to optimize PDF files for adaptive technology friendliness.
Microsoft Office 2000 provides the capability to create tagged Adobe PDF files. Tagged PDF files are mechanisms that make its easier to access content in PDF files. Tagged PDF files contain structural information of a document that is used to describe the structural content of a document rather than the page layout or format. Tagged PDF files are optimized for accessibility and are the most reliable format when using a screen reader.
FrameMaker 6 provides the capability to created structured PDF files. Although a structured PDF file can be accessed by a screen reader, structured PDF is not as reliable as tagged PDF.
Even if you don't create source documents in these access-compatible applications, you can use Adobe Acrobat 5 to transform PDF files to accessible PDF files.
In this article, I show you some steps you can take to create accessible PDF files in both Microsoft Word 2000, FrameMaker 6, and existing PDF files. I focus on
Author documents with accessibility in mind
Converting documents to accessible PDF
How to fix language errors
Making existing PDF files accessible
Adding text descriptions to images
Adding security to accessible PDF files
For Microsoft Office application users, you should have installed Adobe Acrobat 5.0, along with Microsoft Office on your computer. After you have completed the installation, Acrobat appears in the Microsoft application menus as a menu item as well as two small icons on the button bar.
Author Documents with Accessibility in Mind
Whether you are authoring for accessibility or not, creating documents in a structured, logical manner is a good habit. Not only does this aid in accessibility, it helps you keep the contents of documents organized.
It's All in the Version Number
Authoring in Microsoft Word or Adobe FrameMaker? Make sure you are using the software version that best supports accessibility.
Both Word 2000 and FrameMaker 6 provide you with the capability to produce tagged or structured PDF files. If documents are saved in lesser versions of these authoring tools, open documents in the respective newer version, and save the file before creating accessible PDF files.
The Power of Paragraph Styles
One key factor that helps you keep documents logically structured from the onset is using paragraph styles to format text in documents. Microsoft Word 2000 provides predefined paragraph styles and headings. FrameMaker 6 provides predefined paragraph tags.
Paragraph headings, styles, and tags are used to create the structural information in an accessible or tagged PDF file. If you were to use these paragraph styles and tags incorrectly, the structural information is still created based on paragraph headings, styles, and tags; it's just not truly logical, and the document contents may not make sense.
If you are in the habit of pressing the Enter key to skip lines in-between paragraphs, this is a good time to stop. Instead, paragraph tags contain built-in spacing before and after paragraphs in documents that can be changed at any time to accommodate your spacing needs. If you use empty paragraph returns to skip lines instead, these automatically have a paragraph style or tag associated with it that becomes part of that document's logical structure after it's converted to PDF. It doesn't make much sense to have child elements of a structure tree nested under a parent element with no content. Another way of looking at it is to imagine an outline with level 2 list items under a level 1 item with no information.
Other Authoring Guidelines
Here are a few other things to keep in mind while authoring for accessibility.
Alternate Text Description for Images
If your documents contain figures, a screen reader cannot interpret this information. If you include an alternate text description for the image, a no-vision person can at least "listen" to a description of the image. Alternative text descriptions are really helpful when using adaptive technology. Keep in mind that if graphics in documents are used purely for visual decoration purposes, alternative text may not be necessary to aid in understanding documents content.
In Microsoft Word 2000 source documents, you can add alternative text descriptions to images by following these steps:
Click one time on the figure to select it.
Select Format, Picture. The Format Picture window appears.
Click the Web tab.
Type a brief text description in the Alternative Text field (see Figure 1).
When you have finished, click OK. Helpful alternative text is included for the figure, whether you convert to accessible PDF or Web pages.
Figure 1 You can include alternative text for figures in Microsoft Word 2000.
If your authoring application does not provide this capability or if you left this step out, you can always add the alternative description in the tagged PDF file using Adobe Acrobat 5. See "Adding Alternative Text to Figures in Tagged PDF Files" later in this article.
Using Tables, Not Tabbed Text
Tables are used to organize information in documents, and they do their job quite well. A screen reader interprets this information as such, in an organized manner. Using tabbed text in place of a table serves to confuse the user of adaptive technology because this information may not be interpreted correctly, even if it looks good on screen.
Bookmarks are clickable navigation tools in PDF files that make it easier for all readers to jump to various parts of the document. Bookmarks appear in the PDF file as a collapsible hierarchical list of clickable hyperlinks. They are especially helpful for adaptive technology users, aiding in understanding a document's contents at the outset with the ability to quickly jump to various locations in the document.
Bookmarks are created through the magic of paragraph headings, styles, and tags in source documents. That's one good reason why using these correctly is important in the first place.
You can define the tagged paragraphs in the source document that you want to use as bookmarks in the PDF file. For example, if you choose either Heading 1, Heading 2, or Heading 3 to be included as bookmarks, the contents of paragraphs in the source document that are tagged with either Heading 1, Heading 2, or Heading 3 will be displayed in the PDF file as a hierarchical list of clickable hyperlinks.
To create bookmarks in Microsoft Word:
Select Acrobat, Change Conversion Settings. The Acrobat PDFMaker 5.0 for Microsoft Office window is displayed.
Click the Bookmarks tab. The Bookmark Options window is displayed.
Select either one or both choices Under Bookmark Options: Convert Word Headings to Bookmarks or Convert Word Styles to Bookmarks. The matching elements in the following list will automatically include a check under the Bookmarks heading in the list.
Go through the list, and uncheck elements that you do not want to be included as bookmarks. Check elements that you want to be included as bookmarks.
For each checked item, click one time on the number under the Level heading. This determines the organizational structure of the bookmarks after the PDF file is created. For example if you set Heading 1 to Level 1 and Heading 2 to Level 2, then Heading 2 is a subset of Heading 1 (see figure 2).
Click OK. You are returned to the document window.
Figure 2 Microsoft Word 2000 provides a mechanism to define PDF bookmarks.
To create bookmarks in FrameMaker:
Select Format, Document, PDF Setup. The PDF Setup window appears.
Click the Bookmarks tab to access its contents.
Double-click paragraph tag names under the Don't Include list to move them to the Include Paragraphs list (see Figure 3). The content of selected paragraph tags will be included as bookmarks in the PDF file.
Click Set. You are returned to the document window.
Figure 3 FrameMaker's PDF setup window for defining bookmarks.
In FrameMaker 6, move all tags from one list to the other by holding down Shift and clicking the left or right arrow in-between the lists.