The first step in building accessibility into a PDF is to assess it using the accessibility checker tools available in Adobe Acrobat Pro (version 6 and later). You can use the results of the checker as a guide to build accessibility in your documents. Note that although the accessibility checker tools can help to identify areas of documents that may be in conflict with accessibility guidelines, they do not check against all accessibility criteria.
The Quick Check is often the best way to check for accessibility before attempting to use a PDF. The Quick Check will reveal whether a document has real text, structure tags and appropriate security for a screen reader to discern it properly.
To run a Quick Check in Adobe Acrobat Pro 9, from your file menu go to Advanced > Accessibility > Quick Check.
Figure 1: Acrobat Advanced Menu drop down
Quick Check Results [ Adobe Inc, 2009]
Results will vary. Below is a list of possible results and actions you can take.
"This document has logical structure but it is not a Tagged PDF. Some accessibility information may be missing."
Quick Check has found an underlying document structure in the document, so Acrobat will use the available document structure to control the reading order, rather than analyzing the document itself. However, this untagged document structure might be incomplete or unreliable, so assistive software and the accessibility features in Acrobat (such as the Read Out Loud) may not read the page properly. If the reading order of the page seems to be wrong, select Override the Reading Order in Tagged Documents in the Reading panel of the Preferences dialog box.
"This document is not structured, so the reading order may not be correct. Try different reading orders using the Reading Preferences panel. "
Quick Check has found no underlying document structure that Acrobat can use for reading order. Acrobat will analyze the reading order of the document using the current analysis method set in the Reading Order preference, but this PDF might not be read correctly by screen readers. If the reading order seems wrong, select a different option for Reading Order in the Reading panel of the Preferences dialog box.
"No accessibility problems were detected in this quick check. Choose the Full Check command to check more thoroughly. "
Quick Check has found that the PDF contains searchable text, is tagged, has an underlying document structure, and has no security settings that prohibit access for screen readers. To check for other types of accessibility problems that may be present in the PDF, use Full Check.
"This document's security settings prevent access by screen readers. "
Quick Check has found that the PDF has security settings that interfere with screen readers' ability to extract text for conversion to speech. You may be able to use a screen reader with this document if your assistive technology product is registered with Adobe as a Trusted Agent. Contact your assistive technology product vendor.
"This document appears to contain no text. It may be a scanned image. "
Quick Check has found that the PDF contains no searchable text, probably because the document consists entirely of one or more scanned images. This means that screen readers, Read Out Loud, Reflow view, and most other accessibility features--which rely on text as input--will not work with this document
Use the Full Check to perform a more thorough check for many characteristics of accessible PDFs. To run a Full Check, from the file menu select Advanced > Accessibility > Full Check.
You can choose which kinds of accessibility problems to look for and how you want to view the results.
1. Choose Advanced > Accessibility > Full Check.
Figure 2: Accessibility Full Check
2. Select options for how you want to view the results.
You can save the results as an HTML file or as comments that are located where the accessibility problems are detected. Since the comments become part of the actual document structure that needs to be tagged, it is recommended you select the Report option only.
3. Select a page range if you prefer to do a full check on individual sections of a document. For larger documents, it is suggested to check portions at a time for the efficiency.
4. Select an accessibility standard (Adobe PDF, Section 508 (U.S.), or W3C ) from the Name menu, and then select the accessibility options to check for.
5. Click Start Checking.
The results are displayed in the left panel, which also has helpful links and hints for repairing issues.
If you created a report in step 2, the results are available in the selected folder. Clicking on the links highlights the problem areas in the document. The Accessibility Checker panel also provides hints for repair.
Because the Full Check feature is unable to distinguish between essential and nonessential content types, some issues it reports don't affect readability. It's a good idea to review all issues to determine which ones require correction.