PDF Accessibility

PDF is rarely chosen because it's been assessed as the best format for the content.Neil King, Vision Australia

PDF at The University of Melbourne

• PDF is rarely the best format for online content.
• The preferred format for content at The University of Melbourne is HTML.
• If PDF's are published, they must be accompanied by an additional accessible format, such as MS Word.

Document Accessibility

In 2021, WebAIM conducted a survey of screen reader users and asked them 'Which document format do you find most accessible?'

Which document format do you find most accessible?

Response	# of respondents	% of respondents
Word	1036	68.9%
PDF	194	12.9%
EPUB	160	10.6%
Other	113	7.5%

The problem with PDF

• PDF documents can be made accessible, but the vast majority of them are not.
• Accessible and inaccessible PDF documents often look the same, visually, so it is hard for publishers to know that something is wrong.
• HTML contains a lot of semantic elements that are key to users of assistive technologies, such as headings, paragraphs, lists and alt text. These are often lost when exporting to PDF.
• Even if the source document is accessible, if there is a problem with the way it is exported, the PDF output will lose semantic structure.
• It is time consuming and difficult to remediate inaccessible PDF documents.
• If the source document needs to be re-exported, fixes to the PDF version will be lost.

PDF Best Practices

• The gold standard for web content is HTML.
• It is OK to publish alternate versions of web content in Word or PDF, but if only one version is to be published, it should be in HTML.
• Word is preferrable to PDF.

PDF Accessibility Techniques

• The W3C has a set of PDF Techniques for WCAG 2.0 which are a useful guide for PDF creators.
• US Government guide on how to Create Accessible PDFs.

Making Documents Accessible

• Whether it be PDF, Word, or HTML the following issues need to be addressed in order to make a document accessible:

  • Use headings. In HTML this means adding heading tags, e.g. <h1> - <h6>. In Word this means using styles, e.g. Heading 1, Heading 2, Normal.
  • Use lists. In HTML this means adding bulleted and numbered lists, e.g. <ul>, <ol>, <li>. In word this means adding bullets and numbering, e.g. Bulleted, Numbered.
  • Present information in a linear format. In HTML this means using <div> tags and CSS to position elements on the page. In Word this means using Columns.
  • Use table headings. In HTML this means adding <th> tags.
  • Provide alt text for images
  • Identify the language of the document
  • Allow text to be resized
  • Use sufficient color contrast
• W3C PDF techniques
• Acrobat has an inbuilt checker which is very useful
• The PAC PDF accessibility checker for Windows is also very good and is free.
• Mac users can check documents online using axesCheck PDF Accessibility Checker.

Exporting PDF from Word

• Using Windows, click on the Acrobat menu and select preferences.
• Ensure that 'Enable Accessibility and Reflow with tagged Adobe PDF' is checked.
• Publishing the PDF document needs to be done via the 'Acrobat' menu by clicking on the 'Create PDF' button
• Documents can also be saved by clicking on 'File' and then 'Save as PDF or XPS'. You will need to click on 'Options' and ensure that 'Document structure tags for accessibility is checked.

Common misunderstandings about PDF

• Users with vision impairments can't access PDF documents

  Not true. In fact some users with vision impairments actually prefer PDF. The problem is that some users can't access them at all if they are in an inaccessible format. Hence the call for documents to be provided in an alternative accessible format.

• PDF documents are secure and can't be tampered with

  Anything that is published on the web can be changed, including PDF files. Web sites such as www.pdfunlock.com allow users to remove passwords and restrictions from secured PDF files in seconds. Source documents should be archived locally, not stored on the web.

• Publishing in PDF document is quicker because you can just convert it from MS Word

  Not true. Publishing PDF documents that do not discriminate against users with disabilities is often more time consuming than creating a HTML document because there are a number of additional steps and checks that need to be undertaken. Very few PDF documents produced at THe University of Melbourne are accessible to users with disabilities.

• Users who are having problems can just contact us directly

  Users with disabilities will rarely contact publishers about problems that they are having because, like everyone else they have other things to do, and often they don't know where the problem lies, they just know they can't get the information.

Practical Exercise

• Can you spot the problem with this PDF?