Tips to create accessible PDFs

While HTML is universal, PDF files are the de facto way to share documents that need to preserve their formatting across devices. But when creating a PDF, don’t think just about the design of your document, you also need to make sure it’s accessible to everyone who needs to access it. If part of your audience cannot read the document because of an accessibility issue, that’s on the author, not on the reader. It’s important for every technical writer to ensure that the PDFs they create can be used by everyone.

Here are a few quick tips to make accessible PDFs:

Consider if PDF is really the best choice.

PDF may not always be the format that you need. If you just need to distribute information to an audience, PDF may not be the right fit anyway. Consider writing your message as an email or a web page. (You’ll need to make those messages accessible too, but that’s usually easier to do by default.)

Verify that your PDF has tags.

Tags help accessible readers to present information without relying on visual clues. For example, you could write a “heading” using just paragraph text with bold formatting and a larger font size—but that’s not really a document heading. It’s just text. Use a heading style in your original document and your word processor (such as Microsoft Word) should export those headings as tags in the PDF.

Structure your document using headings.

Using headings provides a hierarchical structure to a document, which is very important to readers who rely on accessible technology. Every document should have one (and only one) heading level 1 in it. In HTML terminology, that’s <h1>. In Microsoft Word, that’s Heading 1. Headings should follow numerical order, and not skip levels. That means that heading level 2 should follow heading level 1, and so on. Don’t skip heading levels; you shouldn’t have heading level 1 followed by heading level 3.

Provide alternative text for images.

Images should include alternative text, which will be read by the assistive technology. Include a useful, meaningful description here; don’t just write “image” or some other “placeholder” text. Also, screen readers will usually describe an image as “image” so your alternative text shouldn’t be “image of something.” Writing “four people holding hands in a circle” is a pretty good description of a photograph of four people who are holding hands while standing around in a circle.

Use highly visible colors, or don’t use colors at all.

Many authors like to include colors to highlight important information. For example, you might write a heading in blue so it stands apart from the black text in the rest of the document. Or you might emphasize text using red to provide a warning. But these colors may not stand out for someone who cannot see color, or has other color vision limitations. Also consider situational colorblindness, such as people who otherwise can see in color, but might view your document on a phone late in the evening, when “nighttime” mode puts the display into black and white. If you must use color, ensure that your colors have good contrast with each other and with the background.

More information

To learn more, you can read Microsoft’s knowledge base article about how to create accessible PDFs. Also, Harvard University has a very nice guide for creating accessible PDFs.