Ally PDFs: The Good, The Bad, and The Inaccessible

PDFs and Accessibility in Online Courses

Do you keep coming across the dreaded PDF trio?

❌ This PDF is untagged

❌ This PDF does not have a language set

❌ This PDF does not have a title

If so, you may have a PDF obsession… and might need to consider seeking help for this addiction.
Just kidding! But in all seriousness—PDFs can really suck sometimes, and here’s why we have a love-hate relationship with them.

History of the PDF: Why We Loved it and Why it’s Complicated Now

Where Did PDFs Come From?

Back in the early 1990s, Adobe introduced the Portable Document Format (PDF) as a way to solve a big problem: documents looked different depending on the computer, printer, or software you used. PDFs were designed to preserve formatting for fonts, layouts, images, etc, so that a document would look exactly the same no matter where or how it was opened.

It was revolutionary! Suddenly, you could send a resume, a report, or a flyer and be confident it wouldn’t turn into a mess of weird fonts and broken margins on someone else’s screen.

Fast forward to today’s digital classrooms, and PDFs start to show their age. In LMS platforms like Canvas, we need content that’s easy to read on phones and tablets, accessible to screen readers as well as quick to update and link.

PDFs? Not so much.

They’re static, often hard to edit, and can be a nightmare for accessibility unless they’re carefully remediated. And if you update a PDF, you have to re-upload it, fix all the links, and hope students aren’t still using the old version they downloaded last semester. Talk about time consuming!

Common Accessibility Issues with PDFs

Lack of Semantic Structure
PDFs often don’t include headings, lists, or tables marked up in a way that screen readers can interpret. This makes navigation difficult for students using assistive technology.

Unsearchable or Scanned Text
If a PDF is just an image of text (like a scanned article), it’s not readable by screen readers or searchable by students. These need to be OCR-processed (Optical Character Recognition).

Missing Alt Text for Images
Images in PDFs rarely include alternative text, making visual content inaccessible to blind or low-vision users.

Poor Mobile Experience
PDFs don’t adapt well to smaller screens. Students using phones or tablets may struggle to zoom, scroll, or interact with content.

Inconsistent Tagging
Even when PDFs are “tagged,” the tags may be incomplete or incorrect, leading to confusing reading orders and navigation issues.

Best Practices for Using PDFs in Canvas

Use Canvas Pages or Original Source Files When Possible (best option)

Instead of uploading a PDF, consider using:

Canvas Pages for text-based content

Word documents for editable, accessible text

PowerPoint files for presentations with speaker notes

These formats are easier to make accessible and work better with Ally and screen readers. Plus, even the documentation that Ally provides will tell you to upload the original source file in order to remediate.

Remediate PDFs Before Uploading
Use tools like Adobe Acrobat Pro:

Add proper heading structure

Include alt text for images

Ensure reading order is logical

Run accessibility checks

Provide Alternative Formats
If you must use a PDF, ensure Ally’s alternative formats are enabled so students can choose HTML, audio, or ePub versions.

Avoid Scanned Documents
If you need to use a scan, run OCR first and check that the text is selectable and readable.

Additional Resources

Usability and Accessibility Issues with PDFs
PDF: Still Unfit for Human Consumption, 20 Years Later
Avoid PDF for On-Screen Reading
Why we hate PDFs
PDFs: Understanding the Love-Hate Relationship (And What To Use Instead)