Accessibility Document Conversion

Accessibility Document Formats

PDF Accessibility Overview

The Portable Document Format (PDF) is a file format for representing documents in a manner independent of the application software, hardware, and operating system used to create them, as well as of the output device on which they are to be displayed or printed. The PDF specification was introduced by Adobe Systems in 1993 as a publicly available standard. In January 2008, PDF 1.7 became an ISO standard (ISO 32000-1). The PDF Universal Accessibility (PDF/UA) became an ISO Standard in July 2012 (ISO 14289-1:2012). PDF/UA is meant to be a set of guidelines for creating more accessible PDF. The specification describes the required and prohibited components and the conditions governing their inclusion in or exclusion from a PDF file in order for the file to be available to the widest possible audience, including those with disabilities.

Many applications can generate PDF files directly. This direct approach is preferable, since it gives the application access to the full capabilities of PDF, including the imaging model and the interactive and document interchange features. Alternatively some applications can produce PDF output indirectly and then import the formatted output into the PDF container. Although these indirect strategies are often the easiest way to obtain PDF output from an existing application, the resulting PDF files may not make the best use of the high-level PDF imaging model relied upon to expose the semantics of the document.

The PDF accessibility support lies in the ability to determine the logical order of content in a PDF document, independently of the content's appearance or layout, through logical structure and Tagged PDF elements. Applications can extract the content of a document for presentation to users with disabilities by traversing the structure hierarchy and presenting the contents of each node. PDF logical structure shares basic features with standard document markup languages such as HTML, SGML, and XML. A document's logical structure is expressed as a hierarchy of structure elements, each represented by a dictionary object. The document's logical structure is stored separately from its visible content, with pointers from each to the other. This separation allows the ordering and nesting of logical elements to be entirely independent of the order and location of graphics objects on the document's pages. Such information might include, for example, the organization of the document into chapters, headings, paragraphs and sections or the identification of special elements such as figures, tables, and footnotes. Tagged PDF, that builds on the logical structure framework, defines a set of standard structure types and attributes that allow page content (text, graphics, and images) to be extracted and reused for other purposes, like conversion to other common file formats (such as HTML, XML, and RTF) with document structure and basic styling information preserved; So as to make content accessible to people who rely on assistive technology.

PDF Accessibility Tools

Adobe Acrobat PDF Creator

Although you can create accessible PDF files in several programs, Adobe Acrobat Professional is required to evaluate, repair, and enhance the accessibility of existing PDF files. The Accessibility Checker (available in Acrobat X and XI) is a good tool to ensure that nothing was overlooked in your document. You can convert a file to PDF in Acrobat (Select File, Create PDF and then From File), and if the file format is supported (Microsoft Office), the file should be tagged as it is converted. However, if no tags are present, select Edit, Preferences, Convert to PDF, choose the correct format, select Conversions Settings, and ensure that Enable accessibility and reflow is selected. You should then run the full Checker, select Tools, Advanced, Accessibility and then Full Check.
The Tags pane allows you to view, reorder, rename, modify, delete, and create tags (Select View, Show/Hide, Navigation Panes and then Tags)
Tags Tab Screenshot
The Order pane allows you to change the reading order of the content and tags on the page so it matches the visual reading order (Select View, Show/Hide, Navigation Panes, and then Order)
Order Tab Screenshot

PDFMaker MS-Word Add-In

Create PDFs with PDFMaker for Microsoft Windows is the best choice to create high quality tagged PDF files. With the Adobe add-in installed, you can export to PDF by selecting Create PDF from the Acrobat ribbon.

Microsoft Office PDF Converter

Microsoft Word 2010 and 2013 allows you to create tagged PDF files without installing Acrobat. Convert your document by selecting File, Save as Adobe PDF. The tagging process may not be quite as good as with the Adobe add-in, but most content, such as heading levels, lists, and alternative text for images is exported. If you want to verify the accessibility of the PDF or edit the tags that are created, you will still need Acrobat Professional or another vendor solution. Without a Microsoft Office to PDF professional converter, it is recommended you establish accessibility document creation best practices.

Accessibility Document Creation Best Practices

PDF Accessibility Creator Free Tool

The PDF Accessibility Checker (PAC) is a free tool developed and distributed by the Access For All Foundation to evaluate the accessibility of PDF documents and PDF forms. PAC offers the added possibility of displaying a preview of the structured PDF document in a web browser. The PAC preview shows which tags are included in the PDF document and presents the accessible elements in the same way as they would be interpreted by assistive technologies (such as screen readers). PAC also provides an accessibility report which lists the detected accessibility errors. Clicking the links in the report displays the most probable source of the error within the document.

PDF Document Reader

The Adobe Reader is a Freely distributed PDF Viewer from Adobe Systems which is compatible with Microsoft Accessibility Architecture (MSAA) devices on the Windows platform. It has a number of built in accessibility features including text to speech (Read Out Loud), high contrast display, reflow for large print display, auto scroll, accessibility quick check, and an accessibility setup assistance. It is the only PDF file viewer that can open and interact with all types of PDF content, including forms and multimedia.

Accessing PDF Documents With Assistive Technologies

Accessing PDF Documents with Assistive Technology, by American Foundation for the Blind (AFB) This user guide provides guidance on accessing Portable Document Format (PDF) documents for blind and visually impaired users of screen reading technology. The goal is to enable a better understanding of the issues that affect the accessibility of PDF documents by discussing specific examples, highlighting important principles, illustrating common problems, and presenting suggested solutions.

Document Conversion

Microsoft Word provides the greatest level of screen reader accessibility, and document conversion accuracy. PowerPoint is a good format for face to face presentations, but it is usually not the best format for content on the web. PDF or HTML is often the best format to display PowerPoint presentations on the web. Heading structure and other accessibility information will remain intact if you export the file correctly, and everyone has a PDF reader and browser. If you are comfortable with HTML and CSS, and if your content is intended to be displayed on the web, you could consider creating your own slides in HTML. You would have to create your own "next" and "previous" buttons, and then add in images as well as visual styles. The accuracy of Microsoft Office document conversion depends upon the complexity of the content elements and formats. Quite often manual inspection and accessible updates are required in the converted PDF or HTML file.

PDF Accessibility Conversion Tools

Checkpoint Reference