PDFs Screen reader compatibility
Last updated: January 11, 2020
Screen reader compatibility for PDF accessibility features. Built-in browser PDF engines are used where possible. For IE11, the Acrobat Reader plugin is used.
The results include two types of test:
- Expected to work - these tests show support when accessibility features are used correctly
- Expected to fail - these tests show what happens when accessibility features are used incorrectly (marked with )
Reliability by user agent
The solid area in the graph shows percentage of tests that pass in all tested interaction modes. The cross hatched area shows partial passes that only work in some interaction modes. An example of a partial pass is when form labels are read when tabbing, but ignored in browse mode.
|JAWS Chrome||JAWS 2019.1912.1 with Chrome 79|
|JAWS IE||JAWS 2019.1912.1 with IE11||2 better|
|JAWS Firefox||JAWS 2019.1912.1 with FF68|
|NVDA Chrome||NVDA 2019.2 with Chrome 79|
|NVDA IE||NVDA 2019.2 with IE11|
|NVDA Firefox||NVDA 2019.2 with FF68|
|VoiceOver Mac||VoiceOver macOS 10.14 with Safari 13.0|
|VoiceOver iOS||VoiceOver iOS 12.4 with Safari iOS 12.4|
|WindowEyes IE||WindowEyes 9.2 with IE11|
|Dolphin IE||Dolphin SR 15.05 with IE11|
|SaToGo IE||SaToGo 188.8.131.52 with IE11|
|Average||Including older versions|
The average includes all versions, but some browser/AT combinations have tests for multiple versions (NVDA / JAWS / VoiceOver), while others only have tests for a single version (SaToGo and Dolphin).
Expected to work
These tests use conformant HTML or WCAG sufficient techniques and might be expected to work in screen readers. This doesn't always happen.
Expected to fail
These tests use non-conformant HTML or WCAG failures and are expected to fail in screen readers.
|PDF image with blank (single space) alt text|
|PDF image without alt text|
|PDF no headings|
|PDF table without header markup|
|PDF with doc security|
|PDF with no doc title|
Tests expected to fail (due to authoring errors) are marked with .
- Works in 100% of tested screen readers
- Fails in 1% - 25% of tested screen readers
- Fails in 26% - 50% of tested screen readers
- Fails in 51% - 75% of tested screen readers
- Fails in 76% - 100% of tested screen readers
- Stable - works, or doesn't cause problems, in all versions of a specific combination of screen reader and browser
- Better - works, or doesn't cause problems, in the most recent version of a specific combination of screen reader and browser (improvement)
- Worse - causes problems in the most recent version of a specific combination of screen reader and browser, but used to work in older versions (regression)
- Broken - causes problems in all versions of a specific combination of screen reader and browser
All tests were carried out with screen reader factory settings. JAWS in particular has a wide variety of settings controlling exactly what gets spoken.
Screen readers allow users to interact in different modes, and can produce very different results in each mode. The modes used in these tests are:
- Reading Content read using the «read next» command in a screen reader
- Tabbing Content read using the «tab» key in a screen reader
- Heading Content read using the «next heading» key in a screen reader
- Touch Content read when touching an area of screen on a mobile device
In the «What the user hears» column:
- Commas represent short pauses in screen reader voicing
- Full Stops represent places where voicing stops, and the «read next» or «tab» or «next heading» command is pressed again
- Ellipsis … represent a long pause in voicing
- (Brackets) represent voicing that requires a keystroke to hear