The 508 Compliance Resource Team Notes:
In order to make an Adobe PDF 508 compliant, you need to address several areas: reading order, tagging, layout and formatting, and how to handle images, tables and graphs. You also need to purchase the full version of Adobe Acrobat because the free version does not allow you to create 508 compliant PDFs.
Many things must be considered in order to make a compliant Adobe PDF file. Each element must be tagged whether it is a heading, text, an image, a link, a table, etc. Logical reading orders must be set for each page, and backgrounds and other borders need to be "hidden" from the screen readers. Many times Adobe's "Accessibility Checkers" will find many hidden elements or comments that need to be manually removed, either from the original document source file or inside the full version of Adobe Acrobat.
When using the "Save as PDF" or "Export as PFF" feature in many programs (like Microsoft Word, Microsoft PowerPoint, Microsoft Excel, Adobe Indesign, Microsoft Publisher, etc) you will still need to make sure the file is 508 compliant by manually chceking it and fixing errors. Many of these programs add in extra information, don't tag items properly and/or set the reading order properly. PowerPoint presentations saved as PDFs often work better when saved with one slide per page (some screen readers confuse having 2 slides on a page, and it certainly confuses a visually impaired person who is listening to the screen being read if there is more than one slide per page.)
508 compliant testing and 3rd party verification should be obtained for PDFs that are required to be considered 508 compliant. 508 compliant testing using the latest versions of JAWS and VoiceOver should be done at a minimum. 3rd party 508 compliant testing companies can be found in our link section.
Here are some specific topics in regards to making Adobe PDF files 508 compliant: