PDF accessibility: making documents anyone can read

Roughly one in five people has a disability that affects how they read. If you send documents for a living — proposals, brochures, prospectuses, reports — some of the people receiving them cannot read what you sent.

Usually nobody tells you. They just don’t respond.

This is a practical guide to what actually breaks, and what to do about it.

What “accessible” means here

Four groups of people, four different failure modes:

• Screen reader users need the document’s text and structure exposed to software that reads it aloud
• Keyboard-only users — including many people with motor impairments — need to reach every control without a mouse
• Low-vision users need to enlarge text without it disappearing off the side, and need enough contrast to see it
• People with vestibular disorders need movement and animation to stop when they ask it to

A document can pass for one group and fail completely for another. Contrast doesn’t help if the text is an image.

Why most PDFs fail

The text often isn’t text

Anything scanned — and plenty of files exported from design tools — is a picture of words. A screen reader announces nothing, because as far as the software is concerned there is nothing there.

The test takes five seconds: open the file and try to select a sentence with your cursor. If you can’t, no assistive technology can read it either. And neither can Google, which is a separate problem with the same cause.

It has no structure

Even with real text, a PDF needs tags — an invisible layer describing what each thing is. This is a heading. This is a list. These are the header cells of this table. Read this column before that one.

Without tags, a PDF is marks positioned on a page. Software genuinely cannot tell a heading from a caption, and a two-column layout is often read straight across, interleaving two unrelated sentences into gibberish.

Most exports don’t produce tags unless you ask.

It’s the wrong shape for the device

A PDF has a fixed page size, almost always chosen for paper. On a phone, that page arrives shrunk to about a third of readable size.

For most people that’s mildly annoying. If you have low vision, it’s the whole barrier: zoom in far enough to read, and now you’re scrolling sideways to follow every line. A format that can’t reflow can’t adapt.

Fixing the PDF itself

If it must stay a PDF:

Start with real text. Run OCR on anything scanned. Acrobat does this; so do several free tools. Selectable text is the foundation — nothing else matters until it’s there.

Tag it properly. Acrobat Pro’s Accessibility → Autotag Document is a start, but check the result rather than trusting it. Autotagging reads visual layout and guesses, and it guesses badly on anything with more than one column.

Set the reading order explicitly. This is where most of the real work is, and it’s the difference between a document that makes sense aloud and one that doesn’t.

Add alt text to images that carry meaning. Mark decorative ones as artifacts so they’re skipped rather than announced.

Set the document language and title in the properties. One line each, and screen readers use both.

Check your contrast. Body text needs 4.5:1 against its background. Grey-on-grey looks refined in a design tool and disappears on a laptop screen in daylight.

Then verify. Acrobat Pro’s Accessibility Checker catches the mechanical problems. The free PAC checker tests against PDF/UA properly. Neither can judge whether your alt text is any good.

When the answer is “don’t send a PDF”

Here’s the uncomfortable bit. You can do all of the above properly — it’s a real day’s work per document — and the result is still a fixed-size page that doesn’t reflow on a phone.

If the document exists to be read on a screen, the accessible answer is usually to stop shipping a page layout and ship something that adapts. Text that reflows to the reader’s screen. Type that respects the size they’ve chosen. Contrast that follows their system settings rather than overriding them.

That’s not a criticism of PDF. It’s a format designed to guarantee that a page prints identically everywhere, and it’s superb at that. Screen reading is a different job.

What to demand from a document viewer

If you’re publishing through a hosted reader or flipbook tool, most of them are worse than the PDF — they render every page as a flat image, which throws away the text layer entirely and takes you back to square one.

Four questions worth asking before you commit:

1. Is the real text exposed to screen readers? Not “is there OCR somewhere” — is the text actually reachable by assistive technology on the page?
2. Does everything work from the keyboard? Page turns, zoom, search, panels — with visible focus, and no trap you can’t tab out of.
3. Does it respect reduced motion? A page-flip animation should be replaced, not merely sped up, when the reader’s system asks for less movement.
4. Does it survive high-contrast mode? Windows forced-colors mode breaks a lot of custom interfaces.

For what it’s worth, this is what we built into Living Page: the page text is extracted and exposed as a searchable transcript rather than left as an image, every control is keyboard operable, and prefers-reduced-motion swaps the page-turn for a plain scrolling view instead of just animating faster. High-contrast modes are honoured. We wrote it up in the help centre, including what the reader deliberately can’t do.

I’d rather you asked those four questions of any tool, including ours.

The short version

• Selectable text or nothing. Everything else depends on it.
• Tags and reading order are what make a PDF navigable, and they don’t happen by accident.
• Fixed pages can’t reflow, so a PDF will always be harder work on a phone than something built to adapt.
• If it’s meant to be read on screen, ask whether it needs to be a page layout at all.

None of this is about compliance paperwork. It’s that a document nobody can read is a document that didn’t do its job — and you’ll rarely be told, because people who can’t read what you sent tend to go quiet rather than complain.