Making an online PDF accessible ensures that users with visual impairment can access material that would be inaccessible to them in a printed version. It also helps search engines find PDF files.
However, accessible features for PDFs often do not translate to tablet and mobile platforms, so you may wish to publish HTML versions of your PDF documents as well. One option is to create a summary version in HTML on a webpage, and include the PDF on the page for users who want to read more.
It is relatively simple to make a PDF accessible. Following all the principles of accessibility in the original document will make the conversion easier. Common software programs that convert documents to PDFs are Word and InDesign.
If creating a PDF from a Word document, follow the principles in Word file accessibility. Word offers some options when saving as PDF. Ensure that accessibility-related options are checked. For example, do not allow Word to convert text to bitmaps when a font cannot be embedded (perhaps for licensing reasons) – instead, change the font. Similarly, make sure all tagging is enabled.
If creating a PDF from InDesign, make sure that:
- artefacts are tagged – errors in tagged PDFs can make the document unintelligible to users of assistive technology
- the correct heading levels are applied using styles
- tables are structured correctly
- there is a logical reading order in the articles panel – determined by tagging each story, heading and paragraph
- alt text is added to all images and tables
- metadata (document properties – title, author, subject, keywords and other relevant information) is provided (File > Properties)
- font sizes are at least 9 point – 10–14 point is suggested for body text; the Web Content Accessibility Guidelines also recommend that text should be able to be enlarged to 200% on screen or with magnification software without any loss of content, functionality or quality
- hyperlinks are live
- fonts are embedded
- before exporting from Word, go to Preferences > Output > Save and output; tick Embed Fonts in File
- before exporting, set the following options in the Advanced area of the Export Adobe PDF dialog box
- colour and colour contrast are appropriate
- styles create bookmarks effectively.
When you are ready to export to PDF, ensure that options for hyperlinks, tags and bookmarks are selected, and create the PDF.
Caution! You can turn almost any document into a PDF by installing a printer that prints to PDF. An example is CutePDF, but there are many others. Few, if any, of these create accessible PDFs, so be warned!
Checking PDF accessibility
Open the PDF in Adobe Acrobat (not Acrobat Reader) or other PDF-checking program. Find the Accessibility menu and open Full Check. Choose whether to generate and attach a report (it might be better to do this after any issues have been resolved, as evidence that the document has passed the checks). Generally, leave everything else ticked and run the checker.
Review the issues found by the checker, and fix as necessary. Make as many changes as you can in the program you used to create the document (e.g. add missing alt text, correct broken URLs, tag untagged content) and re-export to PDF.
Repeat the Full Check, and continue to troubleshoot until all issues have been resolved and the accessibility checker reports no further issues.
Things to check manually include that:
bookmarks are all present and go to the correct page
hyperlinks go to the correct destination
images have the correct alt text attached
File > Info > Properties is completed and correct
reading order is correct, especially on pages with complex layout.
Some issues cannot be fixed in the original program and must be completed in Acrobat; you will need to redo them each time you export to PDF:
Set the language for the document (generally English).
Set the reading order to use the document structure.
Change the layout and magnification settings, but be aware that users of assistive technology can override these settings. It is best not to set the document to open in full-screen mode or hide any of the user interface options, because the lack of toolbars could confuse some users.
Add a base URL (e.g. the home page for the online publication).
Add interactivity (e.g. hyperlinks or inputs) to objects such as buttons that you created in the layout program.