Creating accessible PDF documents starts by following accessibility practices during the authoring process. Whether you are using word-processing applications like MS Word or Open Office, or desktop publishing and design tools, such as Adobe InDesign, integrating accessibility into the authoring process will improve PDF document accessibility and deliver content to a wider audience.
The concepts and practices you may be familiar with regarding Web accessibility apply generally when working with PDF documents and Adobe products. For example, Web accessibility concepts such as sufficient color contrast, the use of semantics to designate headings and lists, and the reading order of a document all impact the level of accessibility in a PDF file. More details are available from the Documents page.
Adobe provides online training on its products, with an accessibility focus. Visit Accessibility @ Adobe (Adobe TV) to get started.
Lastly, if you are working with external publishers, vendors, or layout consultants, include accessibility as part of the contracted services. Often times, those parties will have more opportunity to include accessibility during the layout and design process. Waiting to address accessibility in the PDF document once it is complete will be more challenging.
Microsoft Word and OpenOffice Writer offer good support for saving files as accessible PDF versions. Much of the accessibility-related markup from Word or Writer is retained in the resulting PDF output. WebAIM's PDF Accessibility - Converting Documents to PDF is an excellent starting point. Further solutions may be found under the Microsoft Office page.
PDF documents that are image-only will not be accessible to screen reader users nor offer other accessibility support. Optical Character Recognition (OCR) technology, such as that found in Acrobat Pro, can recognize any text in the file and include that text as part of the document. However, it is necessary to ensure that the results are accurate and the text information makes sense. The SCRIBE project is another resource for converting PDF documents into more accessible versions.
To evaluate the accessibility of a PDF document, open the file in Adobe Acrobat Pro and chose View > Tools > Accessibility. This will allow you to perform a quick accessibility check or a full evaluation of all accessibility issues in the file.
Another tool to evaluate PDF document accessibility is the free PDF Accessibility Checker (PAC).
Additional information related to making Acrobat documents accessible includes: