PDF/UA, defined in ISO 14289-1, is the specification intended for improving the accessibility of PDF based on the ISO 32000-1 (PDF 1.7) specification. ISO 14289-1 defines separate requirements for the PDF file format, behaviour of a conforming reader, and behaviour of Assistive Technology (AT) devices. Only the file format requirements are in scope for this paper.
The main features of PDF/UA file format requirements are:
Contents must be tagged in logical reading order.
Meaningful graphics, annotations and numerical formulas must include alternate text descriptions.
Alternate text descriptions for graphics or numerical formulas can be specified by the -ah-alttext property, links can be specified by the ‘-ah-annotation-contents’ property.
Security settings must allow assistive technology to have access to the content.
Including bookmarks in the PDF/UA is recommended.
Annotations, links and multimedia may be included.
The language of the document must be specified.
All fonts must be embedded.