Paul Rayius
VP of Strategic Accessibility | Customer Success & Training
“What is PDF/UA compliance” is a common, but not very complicated, question. “How to achieve it,” though, can sometimes get tricky. In this article, I’ll try to break some of it down for you. (Please note, this article is not intended to be an all-inclusive, exhaustive dissertation on everything related to, or required for, PDF/UA compliance. I will, however, point you to such resources, if you’d like more.)
What Is PDF/UA? Understanding the PDF Universal Accessibility Standard
Simply put, PDF/UA is the PDF standard specifically focused on accessibility. To explain this in a bit more depth, there are a number of different PDF standards. “ISO 32000” (ISO stands for International Organization for Standardization) is literally the standard on “how to make a PDF.” Then, there are sub-set standards for PDF like PDF/A – the “archival” standard. There’s an Engineering standard for PDFs. And there’s PDF/UA. The “UA” stands for Universal Accessibility.
PDF/UA compliance is simply making sure that a PDF adheres to the rules as outlined in the PDF accessibility standard. The ISO standard for PDF/UA is ISO 14289 – currently PDF/UA-1 (ISO 14289-1) is the most widely supported version.
What PDF/UA Does NOT Require (You May Be Surprised)
Before we get into the nitty gritty about how to make a document PDF/UA compliant, I think it’s important to also point out what PDF/UA doesn’t really touch. For example, PDF/UA doesn’t mandate how to ensure PDFs are UA compliant. It also doesn’t mandate user interfaces for PDF rendering, how to store PDFs, or hardware (or software) requirements.
Interestingly, and I think very importantly, PDF/UA doesn’t really mandate what content should or shouldn’t be in a document. For example, while authoring “best practices” might recommend certain content, PDF/UA does not require:
The point is that PDF/UA doesn’t concern itself, much, with the content in the document. But it does have rules for how the document’s content should be handled.
PDF/UA Requirements: What Your Document Actually Needs to Be Compliant
So, what is required?
At the very “base” level, “real content” – in other words, anything that conveys important information – has to be tagged. And those tags need to be in a logical reading order. The correct tag needs to be used for the content. So, for example, while PDF/UA doesn’t require documents to have headings or TOCs, if there’s a TOC in the document, it needs to be tagged that way. And headings need to be tagged as headings, too!
There are other rules, too. For example, regarding headings, IF the document contains numbered heading levels, H1 (Heading 1) has to be the first one and you can’t skip from an H1 to an H3 – you’d need an H2 in the middle, somewhere. Each paragraph is supposed to be in its own paragraph tag. Things can get even more complicated when we start talking about how to tag fillable forms, links, tables, lists, lists inside lists, and so on!
How to Check PDF/UA Compliance: Validation Tools and the Matterhorn Protocol
You may be wondering how on earth you’re supposed to remember all of the rules so you can accurately check your documents! Fortunately, you don’t need to. One popular reference document is the Matterhorn Protocol (from the PDF Association). It lists all of the ways a document could fail PDF/UA-1, and indicates what tests can be done automatically by validation software, and what tests require human verification.
| Check | Example requirement | Method |
|---|---|---|
| Document is tagged | Tags tree is present in the PDF | Automatic |
| Correct tag types used | Headings tagged as H1–H6, not P | Automatic |
| No heading levels skipped | H1 → H2 (not H1 → H3) | Automatic |
| Logical reading order | Content flows as visually intended | Manual |
| Alt text meaningful | Image descriptions are accurate, not empty | Manual |
| Language set correctly | Document language declared (e.g., EN) | Automatic |
In addition, there are a handful of free validation tools out there. Of course, some validators are better than others, so you’ll want to do your due diligence to not only pick a good tool but to also know what the strengths and limitations are. And for full PDF/UA compliance, you’d need to do the manual checks that software can’t do — so you’ll need software that provides the functionality to do those manual checks, too.
How to Achieve PDF/UA Compliance at Scale: Batch Validation and Automated Remediation
You may be thinking to yourself, though, “I have a lot of documents to test” or maybe even, “I have a lot of documents that need to be remediated.” You may wonder how to even begin, how you’re going to address the issues you find, or how you’re going to maintain compliance in the future.
Step 1: Don’t panic, we’ve got you!
That said, many of the validation tools out there can only test one document at a time. However, with PDFix, even with the free, PDFix Desktop Lite, you can automatically test batches of documents all at once! (And, yes, you can do the manual checks, too!) This can help you figure out where you stand, how many documents pass, how many fail, and even what types of issues you have in your documents. Then, you can more efficiently devise a plan to address the issues.
And, unlike the other remediation solutions out there, where you can only remediate one document at a time, with PDFix Desktop Enterprise or PDFix SDK (Software Development Kit), you can even remediate documents in batches, automating much, if not all of the work!
PDFix is the real, scalable gamechanger for PDF remediation to not only put the fire out but also to help your organization maintain PDF/UA compliance as new documents are created!
I hope this article has been helpful to explain a little bit about what PDF/UA is, what PDF/UA compliance is, and how to achieve it. If you’d like to learn more, we’d be thrilled to talk with you!
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PDF/UA Resources & Further Reading
Frequently Asked Questions
What is PDF/UA?
PDF/UA compliance means making sure that a PDF adheres to the rules outlined in the PDF accessibility standard. “UA” stands for Universal Accessibility. The specific ISO standard for PDF/UA is ISO 14289 – and PDF/UA is a sub-standard of ISO 32000, which is the core “how to make a PDF” specification. In short: ISO 32000 defines how to build a PDF; PDF/UA defines how to make that PDF accessible to everyone.
What does PDF/UA stand for?
PDF/UA stands for PDF Universal Accessibility. It is the ISO standard (ISO 14289) that defines the rules for making PDF documents accessible to people who use assistive technologies such as screen readers, braille displays, and other accessibility tools.
What is the difference between PDF/UA and WCAG?
PDF/UA (ISO 14289) is the accessibility standard specifically written for PDF documents, covering how content must be tagged, structured, and ordered so that assistive technology can read it correctly. WCAG (Web Content Accessibility Guidelines) is a broader standard written primarily for web content. The two standards complement each other – a PDF/UA-compliant document also goes a long way toward WCAG conformance for PDF-based content, but they are separate specifications with different scopes.
Is PDF/UA same as ISO 14289?
Yes. PDF/UA is the informal name for ISO 14289, the international standard for accessible PDF documents. The current widely-supported version is PDF/UA-1 (ISO 14289-1). A newer version, PDF/UA-2 (ISO 14289-2), exists but does not yet have broad tool or software support – though that is expected to change.
Do PDF/UA compliant documents require headings?
No – and this surprises many people. PDF/UA does not require headings to be present in a document at all. However, there is an important condition: if a document does contain headings, they must be tagged correctly as heading elements, and numbered heading levels must be sequential — you cannot skip from H1 directly to H3, for example. The same logic applies to tables of contents, hyperlinks, and fillable form fields: PDF/UA does not require them to exist, but if they do exist, they must be handled correctly.
How do I check if the PDF is PDF/UA compliant?
You can check PDF/UA compliance using validation tools. Some checks – such as whether the document is tagged, whether heading levels are in sequence, and whether the document language is declared – can be done automatically by software. Other checks, such as whether the reading order makes logical sense or whether image alt text is meaningful rather than just present, require human verification. A useful reference for understanding which checks are automatic versus manual is the Matterhorn Protocol, published by the PDF Association. PDFix offers both an online validator and a desktop validation tool that covers both automatic and manual checks.
What is Matterhorn Protocol?
The Matterhorn Protocol is a reference document published by the PDF Association that lists all of the ways a PDF document can fail PDF/UA-1 compliance. It is an essential companion to the PDF/UA standard itself. The Matterhorn Protocol is especially useful because it clearly separates which compliance checks can be performed automatically by validation software from those that require human review. Anyone working on PDF/UA compliance – whether checking documents manually or building automated validation into a workflow – should be familiar with it.
How do I fix a PDF that fails PDF/UA validation?
Fixing a PDF that fails PDF/UA validation is called remediation. The process involves identifying which specific rules the document violates – using a validator – and then correcting those issues, such as adding or correcting tags, fixing reading order, or adding meaningful alternative text to images. For a small number of documents this can be done manually. For larger volumes of documents, tools like PDFix Desktop or PDFix SDK allow you to remediate documents in batches, automating much or all of the remediation work rather than fixing each file one at a time.
Can I test multiple PDFs for PDF/UA compliance at once?
Most PDF/UA validation tools can only test one document at a time. PDFix is an exception – even the free PDFix Lite allows you to run batch validation across multiple documents simultaneously. This makes it possible to quickly assess a large document library: how many documents pass, how many fail, and what types of issues are most common. That information lets you plan remediation efficiently rather than discovering issues one file at a time. For batch remediation a quick fixes – not just batch validation – PDFix Desktop and PDFix SDK can automate the fixing process across large volumes of documents.
