The Universal Benefits of PDF/UA
With over a billion people around the world affected by a disability, there are good reasons to make digital content more accessible. When it comes to digital PDF documents, the PDF/UA (Universal Accessibility) standard aims to provide users with disabilities with a premium digital experience.
With over a billion people around the world affected by a disability, there are good reasons to make digital content more accessible. When it comes to digital PDF documents, the PDF/UA (Universal Accessibility) standard aims to provide users with disabilities with a premium digital experience. To ensure this, PDF/UA extends the general specification of PDF 1.7 with some additional requirements, PDF applications and assistive technologies (AT).
By improving this general accessibility for people with disabilities by adding more structure and metadata, PDF/UA also opens up automatic reading options that benefit all users, with or without disabilities. In this blog, we explore these benefits.
Improved navigation and display on mobile devices
People with motor disabilities are often limited by their input controls when viewing and navigating through a PDF document. Ideally, they can navigate the document using an adaptive keyboard, but often, even with eye tracking software, a sip and puff switch, etc., it’s easy to see that the visualization and navigating a document with these devices requires more effort than the traditional mouse and keyboard setup.
The PDF/UA requirements are intended to ensure that browsing with these AT devices can occur as efficiently as possible. To do this, it requires marking structural elements and mapping them into a structure tree that represents a logical reading order.
Yet able-bodied users also use devices with limited input controls on a daily basis. Navigating through complex and inaccessible documents on our phones and tablets can be a frustrating experience. Luckily, we can already alleviate a lot of that frustration by enabling content to automatically adjust to a readable size and layout.
Additionally, navigation can be made easier by allowing the user to jump to certain structural elements of the document. This can only happen if the document is properly tagged.
Provisions for text-to-speech
Thanks to text-to-speech, it is now possible to let your car or your home assistant (like Alexa, Siri, Google Assistant, Cortana or the open source home assistant) read your documents for you, while you can go about your business business and have your hands free.
Since PDF/UA compliant documents are aimed at visually impaired users who often use screen readers, these documents will already have the correct reading order, language detection, and alternative descriptions for images in place to potentially make it a much better experience.
We say potentially, because home assistants today are not yet taking full advantage of the provisions of PDF/UA. However, web content-focused initiatives like Google Read It aim to make long-read content available in any form, and PDF is certainly an essential format for long-read content.
Improved conversion to HTML: ngPDF
ngPDF represents the next generation of PDFs and focuses on the challenge of making PDFs a first-class citizen of the web, where users consume information through a wide range of devices with divergent screen sizes.
Tags in PDF/UA and the structure tree are comparable to HTML tags and the DOM (Document Object Model) they form, and this similarity is exactly what ngPDF exploits. It does this by using an algorithm developed by the PDF Association that can produce a reliable HTML presentation of a properly tagged PDF document.
For example, the PDF structure element of a paragraph P translates to a p tag in HTML.
You can learn more about ngPDF in the white paper co-authored by iText and Dual Lab Web-Friendly PDFs with ngPDF.
The derivation algorithm that forms the core of ngPDF in action. By converting the tagged PDF to HTML, we get a responsive solution that’s easy to view on all screen sizes.
Improved SEO (search engine optimization)
Making a PDF document accessible makes it easier for search engines like Google to crawl the web. This is an important part of SEO and improves the likelihood that your PDF will find its way to your target audience. Google has been indexing PDFs since 2001, and today PDFs are even included as snippets.
How does PDF/UA help? First and foremost, PDF/UA requires text-based PDFs, rather than image-based PDFs. This makes the body text of the document searchable. If you want to convert your PDF files based on scanned images, you can do so using an OCR (Optical Character Recognition) tool such as iText pdfOCR.
Since we also tag structural elements such as headings (H1, H2, H3, etc.) in PDF/UA, search engine algorithms can navigate the document structure and determine which content is most important . PDF/UA also requires alternative descriptions for images, not only allowing access by screen readers for people with visual impairments, but also allowing web crawlers to understand what an image represents.
Finally, PDF/UA requires that the language of all document content be specified so that the web crawler immediately understands in which language (or languages) the document is written.
Many PDF/UA requirements improve machine readability by adding structure and metadata to a PDF, thereby benefiting users with and without disabilities. Making documents accessible was already the right thing to do, as it greatly influences access to information for people with disabilities.
And because accessibility is mandated by law in many countries, failure to provide accessible materials can create legal liability for organizations. We have now learned that the universal benefits of PDF/UA add an extra incentive to make your documents compliant.
For more general information about the standard, requirements, validation, key stakeholders, laws and regulations, and iText’s PDF/UA capabilities, we recommend reading the recently released e-book: PDF/UA: The inclusive document format.