Accessibility. Tagged structure, reading order, alternative text.
| ISO reference | ISO 14289-1:2014 |
|---|---|
| Based on | PDF 1.7 |
| Purpose | Accessibility |
| Transparency | Permitted |
| Colour spaces | Unrestricted, but colour alone must not convey meaning |
PDF/UA is the accessibility standard for PDF. UA stands for Universal Accessibility, and the requirement it encodes is that the document must be machine-readable in a way that reflects its meaning, not just its appearance.
That distinction is the whole standard. A PDF that looks perfect can fail completely.
A PDF stores marks on a page. Without extra information, a heading is just larger text, a table is just aligned lines, and a two-column layout is just two groups of characters. A screen reader has no way to know the reading order, or that a row of numbers belongs to the column header three inches above it.
Tagging supplies that missing structure.
Text that has been converted to outlines is a common failure. It looks identical and is no longer text at all.
WCAG is the broader web accessibility guideline set; PDF/UA is how those principles are expressed in PDF specifically. Conforming to PDF/UA is generally how a PDF satisfies the relevant WCAG criteria.
PDF/A-1a overlaps but is not the same. A-1a requires tagging for archival reasons, so a file can meet both, but PDF/A is about longevity and PDF/UA is about usability. Meeting one does not automatically mean meeting the other.
Public sector publishing in much of Europe and North America, education, and any organisation with accessibility obligations. If a document is going on a government website, assume it applies until told otherwise.
Conformance is not something you can confirm by eye. Upload a PDF and Filecheck reports which standard it actually conforms to, and what would have to change. Free, no signup, files deleted after processing.