To make a PDF accessible, you must understand how screen readers read them. Screen readers help people with visual disabilities by reading the text out loud. To do this correctly, the PDF has to follow a clear reading order. Today’s post explores the different layers of a PDF that affect reading order and what you need to do to make your PDF work well with screen readers like JAWS and NVDA.
Video Guide
What Is PDF Reading Order?
A PDF has three main systems that tell screen readers what to read and in what order:
- Tags Panel: Lists the structure of the content (like headings, paragraphs, etc.). This is what screen readers use most of the time.
- Content Panel: Shows the actual order of objects on the page.
- Reading Order Panel (Z-order): Shows how things are stacked or layered visually.
To make your document easy to read, all three panels should be aligned.
Testing with a Sample Document
Follow along with our Video Guide above.
We created a Word document with one heading and four lines labeled “first,” “second,” “third,” and “fourth.” We saved it as a PDF and used screen readers to test how they read the file.
Testing Reading Order with JAWS
At first, JAWS read the content in the order shown in the Tags Panel. Even when the tags were moved around, JAWS still read everything in the expected order. But when both the Tags Panel and the Content Panel were changed, JAWS followed the Content Panel. This shows that JAWS mostly follows the Tags Panel but can switch to the Content Panel depending on the setup.
The Content Panel decides where and in what order things appear on the page. If this order doesn’t match the Tags Panel, screen readers can get confused.
Note that saving and reopening the file changed how the screen reader read our test document.
Testing Reading Order with NVDA
When testing the same PDF with NVDA, it kept crashing. That made it impossible to see exactly how NVDA reads the PDF.
Why All Panels Should Match
The best way to make sure your PDF works with screen readers is to match all three panels: Tags, Content, and Reading (or Z) Order. If they all say the same thing, then screen readers will read the PDF correctly.
Testing Reading Order with Adobe Read Aloud
For fun, we tested the reading order with Adobe Read Aloud. This is a text-to-speech tool that reads visible text out loud. However, it doesn’t read semantics like headings or alternative text, so it is not a good tool for checking real accessibility.
Tips for Testing the Reading Order of a PDF
Here’s what you should do:
- Keep the Tags Panel, Content Panel, and Reading (or Z) Order Panel in the same order.
- Test your PDF with more than one screen reader.
- Always save and reopen the file before testing.
To make PDFs accessible, focus on the Tags Panel, but don’t ignore the Content and Reading Order Panels. They all play a role. Matching all three gives you the best chance of having a file that screen readers can read smoothly. It also ensures everyone can access your content equally.
Let me be your champion for inclusion. I offer tailored solutions (and self-paced courses!) to ensure your documents meet and exceed compliance expectations. For more detailed insights, tutorials, and in-depth discussions on accessibility and related topics, don’t forget to check out my YouTube channel: The Accessibility Guy on YouTube. Subscribe for regular updates!
