Two new Technical Notes addressing PDF/UA-1 implementations

As requested by TC 171 SC 2 WG 9 at its meeting in Berlin in September 2025, the PDF Association has now published two new Technical Notes developed by the PDF/UA Technical Working Group (TWG), addressing interoperability questions encountered when creating and consuming PDF/UA-1 documents.

These Technical Notes do not alter the requirements of ISO 32000-1 or ISO 14289-1. Instead, they are intended to clarify practical issues associated with PDF 1.7 and PDF/UA-1. 

Use of ActualText on Figure structure elements

Technical Note 001 addresses an important edge case in accessible PDF: content other than text whose purpose is to convey textual meaning.

PDF/UA-1 requires such content to be tagged with a Figure structure element (tag). However, an object that visually represents text does not necessarily have the semantics normally associated with a figure.

PDF/UA-1 TN-001 describes an approach that satisfies PDF/UA-1 while preserving the intended textual meaning for assistive technology, and provides examples. It recommends placing the Figure tag within an appropriate block- or inline-level structure element, supplying an ActualText value representing the textual content, and explicitly specifying a Placement of Inline for that Figure tag.

The Technical Note explains that accessibility APIs should expose such ActualText value as plain text rather than causing assistive technology (AT) to announce the content as a figure or image.

Reference structure elements containing links

This document addresses the specific interaction between Reference tags and link annotations. 

Reference tags are used for table-of-contents entries as well as footnote and index references. In PDF 1.7 a Reference tag does not, in-itself, imply interactivity. When the user includes a link (via a link annotation), PDF/UA-1 requires that the annotation is enclosed in a Link tag.

Under PDF/UA-1, therefore, Link tags always enclose link annotations, while a Reference tag may or may not include one (or more) links, but if it does, a Link tag is required.

Both Reference and Link structure elements are exposed to assistive technology, which sometimes causes a link to be announced twice. PDF/UA TN-002 clarifies that a duplicate announcement is undesirable, and that viewer software should not interpret the presence of both structure elements as requiring the link to be announced more than once.

The Technical Note also looks forward to PDF 2.0, in which link annotations may be direct children of either Link or Reference tags. Consuming software should therefore be prepared to support both models.

Conclusion

Together, these Technical Notes address narrow but significant issues for AT users.

By documenting expected authoring and consumption behavior, the PDF/UA TWG aims to improve consistency across PDF creation tools, viewers, accessibility APIs and assistive technologies, thereby improving the experience of people using accessible PDF.

Comments are welcome! Please use the PDF Association’s Report an issue GitHub repository.