Portable Document Format files, also known as PDFs, are one of today’s most popular document types. Their versatility and extra features such as electronic signatures or password protection means PDFs are used across the world for spreadsheets, employee contracts, invoices, school assignments and reports, and many more. However, an often-overlooked aspect of PDFs is their accessibility.
They are considered universal documents: regardless of what software or device someone is using, they will be able to open a PDF file. But this doesn’t mean they will be able to read the PDF if the necessary accessibility features are missing. Designing a PDF with accessibility in mind right from the start will give all your users a good user experience.
Guidelines on making accessible PDFs
1. Create your file on an accessible editor. There are many different editors to choose from when creating a PDF file, but the accessibility of the final document will vary. Platforms such as Microsoft Word or Adobe InDesign are more likely than online templates to retain accessibility features when exported to PDF.
The onus is on the designer to make their PDF accessible to people with disabilities. Using an accessible editor will make this easier, and where possible, designers should start from scratch in Adobe Acrobat Pro, which includes a variety of accessibility tools for use.
2. Add alternative text descriptions to images. This benefits people who are blind or have low vision. While they might not be able to receive information from an image, a screen reader allows them to listen to a PDF being read out loud. Alt text should be as concise yet as descriptive as possible, relaying only what is necessary for users to understand why an image has been included in a PDF in the first place.
3. Avoid images of text. Infographics and similar diagrams can be eye-catching and a memorable way to show information, but they are difficult to make accessible. Unlike regular text, images cannot be customised to suit a user’s need for a specific font or size or colour, and the text contained inside an infographic may be too long to put into alt text. As much as possible, actual text should be used to give information.
4. Assign a reading order to your PDF. Some designers may choose to insert text in a document only after images have been added. Others may do it the other way around. If left unchanged, the order in which elements were added to a PDF remains as its final reading order.
The assigned reading order dictates exactly what assistive technologies like screen readers are reading to users. In this case, they will incorrectly read all the images first then the text, regardless of how they appear on screen. Software like Adobe Acrobat Pro allows you to assign or change the reading order of a PDF, and therefore ensure it is read in a logical way to assistive tech users.
5. Use a high-contrast colour for the text in your document. The WCAG, the international standard for web accessibility, states that text should have a contrast ratio of at least 4.5:1 against its background. This benefits people with low vision or colour blindness, who may struggle to read certain colour combinations like grey text on white or yellow text on pink.
6. Organise your document using headings. Text-based documents such as annual reports or school assignments might be very lengthy. Separating the document into sections and adding a heading to each section will help with readability and navigation, especially for people with learning disabilities or who use assistive tech.
After the content and design of a PDF has been finalised, it should always be reviewed for accessibility before being sent to others or uploaded to a website. Making PDFs more accessible brings us closer to a future where everyone can equally experience and engage with digital content without any barriers. Contact the IA Labs team with any questions or for support around creating accessible PDFs for your organisation.