Tagging your PDFs applies markup that defines the structure of each document. That ensures that your documents work well with screen readers and other assistive technologies — and can improve compliance with the Americans with Disabilities Act (ADA), Section 508 of the Rehabilitation Act, and various other non-discrimination laws.
But despite their good intentions, many document authors make basic mistakes when tagging their documents. By following the Web Content Accessibility Guidelines (WCAG), you can avoid those mistakes and provide better resources for your audience.
1. Relying on automatic PDF tagging for accessibility
Tagging your PDFs fulfills WCAG 2.1 Success Criterion (SC) 1.3.1, “Info and Relationships,” which requires that “information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text.”
Adobe Acrobat has an excellent feature for meeting this guideline: Make Accessible. To access this feature, go to Tools > Action Wizard > Make Accessible.
The feature automatically applies tags to your document, and if you have a simple PDF, it might handle all of the hard work for you. However, like all automated accessibility tools, it’s not 100% perfect.
You’ll need to review the output carefully. Acrobat’s Full Check/Accessibility Check feature automatically scans your document for common tagging issues and presents a report. Adobe provides a guide for using Accessibility Check and reviewing its output.
When manually reviewing your PDFs for accessibility, keep these tips in mind:
- Subheadings (also called heading tags) should be nested in logical order. That means H2 subheadings always appear below an H1, and H3 tags always appear below an H2. Read more about the importance of sequential subheading tags.
- Make sure subheadings and image descriptions contain accurate, descriptive information.
- Review the best practices of writing image alternative text, which can be applied to PDF image descriptions.
- Use the Tools > Accessibility > Reading Order tool to make sure that the tags tree has the same reading order as the document’s visual presentation.
Related: Does WCAG Apply to Web Documents?
2. Not including a descriptive title for your PDF
Title tags are important for accessibility. Web pages must have a title tag to meet WCAG SC 2.4.2, “Page Titled,” and the authors of WCAG recommend using the PDF Title entry to ensure conformance with this criterion.
So, why are page titles important for accessibility? If a person uses a screen reader or if they have a condition that affects their cognition, they may review the title of a document before opening it. Without the title, the user would be forced to read through a section of the document to determine whether it contains the information they need.
When writing PDF titles, keep these tips in mind:
- The title must be descriptive. A generic title like “web form" doesn’t give the user enough information, so include relevant details about the document’s contents.
- The title must be unique. For example, if you have several PDFs titled, “tax form,” but they’re specific to certain types of users (such as contractors and employees), you’ll need to revise the titles — even if your website links to each PDF with appropriately descriptive link text.
- Titles for similar documents should use consistent naming conventions. For example, if your last financial report was titled, “Our Company’s 2021 Financial Report,” don’t name your next report “2022 - Financial Report for Our Company.”
Finally, remember that if you’re creating a document in Microsoft Word or another word processor, Adobe Acrobat’s auto tagging feature will usually use the title of the original document as the title entry.
Once again, you’ll need to review the output, and you may need to change the PDF’s title through the document properties. Simply renaming the PDF won’t update its title entry.
3. Including watermarks in your PDF tag tree
If your PDF includes a decorative watermark (for instance, a watermark of your company’s logo), it doesn’t need to be included in the tag tree. If your watermark appears on every page as part of the tag tree, it may break up the flow of your content for screen reader users.
Adobe notes that the best way to add a watermark is to insert an untagged PDF of the watermark into a tagged PDF. This leaves the watermark in place for visual-first users without interfering with screen readers.
If a watermark contains important information about the document, make sure that information is available elsewhere. For example, if the watermark provides the year of publication, include that info in the PDF’s title entry or within the content.
All PDFs need appropriate tags to be useful for people with disabilities
We’ve addressed several common PDF accessibility issues, but this isn’t a comprehensive list. Your PDFs also need accurate language tags, bookmarks (for larger documents), and appropriate color contrast.
Acrobat’s Full Check/Accessibility Check can check for many issues, but others require human review. For document creators, learning a bit about the four principles of accessibility can be enormously helpful — when you understand how barriers affect your real-life users, it’s much easier to fix those issues.