Avoid publishing PDFs on the University website

The Portable Document Format (PDF) was created in 1992 to replicate the exact layout of a document regardless of what software was being used to view it. It is based on the PostScript format used by printers.

While PDF is an extremely useful format for transferring files intended to be printed, it is extremely poor when used in the multi screen world 30 years after it was created.

Why we should not use PDFs on the website

Using PDFs on websites is problematic because:

• they take users out of the website and into a software application, resulting in a poor user experience (particularly on mobile)
• they are harder to find, maintain, and update than HTML content which can lead to users engaging with inaccurate and out of date content
• they are difficult to use if someone has accessibility needs. For example, you cannot change the background colour or text sizes easily.
• browser shortcuts for tasks like zooming and scrolling don’t always work
• search engines do not always rank PDF content as highly as HTML content
• it’s difficult to get analytics information from PDFs and understand how users are interacting with the content
• PDFs are often significantly larger than the equivalent HTML pages. To minimise data usage and reduce environmental impact, we are keen to reduce the number of PDFs that we host

Accessibility monitoring

Content on the University website has to be fully accessible under the Public Sector Bodies (Websites and Mobile Applications) (No. 2) Accessibility Regulations 2018. 

Compliance is actively monitored by Government Digital Service (GDS), part of the Department for Science, Innovation and Technology. 

As of October 2024 we have to adhere to the Web Content Accessibility Guidelines WCAG 2.2 AA standard.

Broken links in PDFs

Broken links lead to a poor user experience and negatively affect our website search rankings.

Links within PDF documents are a major problem as, when these break, the entire PDF needs to be replaced with a fresh file. This is not always easy as the original non-PDF file (whether Word, InDesign, or something else) may not exist.

With HTML, if the destination web page is updated or deleted, we can easily detect and update any broken links.

Web Services reserve the right to remove PDFs from the University website if they are found to contain broken links.

The myth of "Accessible" PDFs

PDF/A is a version of PDF with improved accessibility features and all PDFs that are uploaded to the University website must be compliant with this. 

Regardless of these improvements it retains many of the inherent flaws with the PDF format. The accessibility improvements only help the subset of users who use specialised accessibility software such as a screen reader.

A PDF can meet the PDF/A standard if:

• the document contains text and is searchable
• the language and title of the document are defined
• the document is created using tags which provide a logical reading order
• all links, images, and forms have descriptive text
• it contains navigational aids such as bookmarks
• tables, if used, are properly tagged 
• security settings are configured correctly
• form fields are accessible
• the colour contrast between the background and the text in the foreground meets legal requirements (a ratio of 4.5:1)
• it's possible to use the keyboard to navigate through the content

When content may be published as a PDF

There are exceptional circumstances when you can request content to be published as a PDF.

These include:

• Downloadable forms to be printed and completed offline
  • PDF forms should not be designed to be completed online. GDS do not regard these compatible with WCAG 2.2 AA
• Extremely detailed multi-page legal documents and reports
  • Web Services are working on improvements for long pages to avoid this.
• Where there is a legal requirement to publish a formal, signed document
  • The copy of this document should be published as HTML in the first instance, with the signed document available in addition.

You should not publish content in PDF format when:

• It replicates existing content on the University website that performs a similar function.
• The content needs to be reviewed regularly to remain accurate. An example of this would be immigration content that is impacted by changes in UK government policy or guidance. 

PDFs should always be added to the website using the corporate information or guide content types. This allows these pages to act as a gateway to the PDF and provides helpful information to the user such as summary, last updated, and file size information.

Images in PDFs

You should:

• provide descriptive alt text for all images 
• indicate all decorative images using the accessibility checker

For accessibility, if text is embedded within complex images such as flowcharts and process diagrams then it should enhance the existing text rather than be a substitute for this information. 

A data table should be provided with the equivalent information when chart and graph images with embedded text are used.

Use an accessibility checker

If you have to create a PDF you should ensure that the source document (for example, Word .docx file) is accessible before you convert it to PDF.  Find out how to improve PDF accessibility 

When you have converted a document to PDF you then should run it through the accessibility checker to check for any issues against PDF/A. You can do this using Adobe Acrobat Professional (go to Tools > Accessibility > Accessibility Check).