Why PDF Accessibility Matters
Millions of people use assistive technologies such as screen readers, Braille displays or specialised input devices to access digital content. A PDF that exists only as an image scan or lacks structured tags is completely inaccessible to these users, the screen reader finds no text to read, form tab order is missing, and images have no alternative text.
Accessibility is therefore not an optional enhancement but a fundamental requirement for truly usable documents.
Legal Requirements in the EU and UK
Public Sector Bodies
The EU Web Accessibility Directive (2016/2102) requires all public sector bodies to make their digital content, including downloadable documents, accessible. Member states have implemented this through national legislation. In the UK, the Public Sector Bodies Accessibility Regulations 2018 impose similar requirements.
Private Sector: European Accessibility Act
The European Accessibility Act (Directive 2019/882) extends accessibility requirements to private businesses in regulated sectors, banking, insurance, e-commerce, telecommunications, passenger transport. National implementation laws came into force across EU member states with full application from June 2025.
Technical Requirements for Accessible PDFs
Tagged PDF Structure
The most important characteristic of an accessible PDF is tags. These invisible structural elements define what is a heading, a paragraph, a list, a table or an image. Without tags, a screen reader cannot determine the logical reading order. Tags are generated when exporting from Word or InDesign if the appropriate option is enabled.
Alternative Text for Images
Every image that carries meaningful information needs alternative text (alt text). This briefly and accurately describes what the image shows. Purely decorative images receive empty alt text so screen readers skip them.
Correct Reading Order
Even when a PDF looks visually correct, the internal order of content elements may differ. Screen readers follow this internal order, not the visual layout. In multi-column layouts or documents with offset text boxes, this can produce a completely nonsensical reading sequence.
Document Title and Language
The document should have a meaningful title entered in the document properties. The document language must also be correctly specified so that the screen reader applies the right pronunciation rules.
Colour Contrast
Text must have sufficient contrast against the background. WCAG guidelines require at least 4.5:1 for normal text and 3:1 for large text. Light grey text on a white background, common for disclaimer text in documents, is problematic.
No Restrictive Encryption
Password protection and restrictive permissions can prevent assistive technologies from accessing text content. If a document needs to be accessible, access by screen readers must not be blocked.
Creating Accessible PDFs from Office Applications
Microsoft Word and PowerPoint include a built-in accessibility checker under the Review menu. It identifies missing alt texts, reading order problems and unstructured tables. Fix all identified issues before exporting to PDF. When exporting, select the option to include document structure tags for accessibility.
Checking and Retrofitting Existing PDFs
For existing PDFs, inspection tools are available. Adobe Acrobat Pro includes a full accessibility check against the PDF/UA standard. Free alternatives like PAC 2024 (PDF Accessibility Checker) check documents against the international standard ISO 14289 (PDF/UA).
If you want to convert a scanned PDF into an accessible document, start with the OCR tool to make the text machine-readable first. The document can then be further prepared with professional tools.
Minimum Requirements for a Conformant Document
- Document title included in metadata
- Document language set correctly
- All content tagged (headings H1-H6, paragraphs, lists, tables)
- Alternative texts for informative images
- Logical reading order verified
- Sufficient colour contrast (at least 4.5:1)
- Read access by screen readers not restricted
Conclusion
Accessible PDFs are not optional, they are already legally required for public sector bodies and mandatory for regulated private sector businesses from 2025. Technically, an accessible PDF is not complicated: anyone who structures source documents with proper headings and alt texts from the start has completed most of the work. Retrofitting existing documents is more labour-intensive but achievable with the right tools.