Accessibility guidelines for Portable Document Format (PDF)

Aligning all text to the left (in languages that are read from left to right) makes it easier for people to see where each line begins. This includes text in tables, headings and diagrams.

Avoid justified text, where both the left and right edges of each line are aligned with both margins. This creates uneven gaps between words, making it harder to read.

Avoid centred text: this makes it difficult to see where each line begins.

People with reading difficulties can struggle to follow long lines of text, so keep them to a maximum of 60 to 70 characters.

A structured layout with a uniform heading structure enables screen readers to read content aloud in a logical order.

A heading should be clear and meaningful, defining what the section of the document is about.

Include alt text on images, including photographs, charts, icons, logos and diagrams.

Alt text is a short description of the image that is read aloud by screen-reading software. It is essential for users with visual impairments to help them understand the document.

Sometimes it isn’t necessary for a graphic to be read. For example, you might not want logos in the footer to be read on every page. In this case, don’t add the alt text to the box. Instead, mark them as decorative. This will instruct a screen reader to skip this graphic without altering the reader’s understanding of the content.

Read our full alt text guidelines

Complicated writing can be confusing and hard to understand. It can be particularly difficult for people with dyslexia, autism or other cognitive conditions, or for people whose first language isn’t English.

When writing, think about the words you use when having a conversation. Remember that our brains take in information more easily when it’s broken into small chunks.

It’s good practice to read your writing aloud, line by line, removing unnecessary words and rewriting sentences if they seem too long. If you come across large blocks of text, break them up into shorter paragraphs.

• Instead of: We are a leading NGO with a presence in more than 30 countries, building synergies to facilitate the avoidance of blindness and increasing capacity to promote equality of opportunity for people with disabilities.
• Try: We are an organisation working in more than 30 countries. We prevent avoidable blindness and fight for disability rights.

If possible, convert from Microsoft Office to PDF using Adobe Acrobat. This will ensure all accessibility elements are picked up.

Provide a meaningful filename that describes the topic of the document. This will make it easier to find the document and help people to quickly understand the subject matter. It will also make your document look more professional.

• Instead of: Doc33464_Final_Approved_V3
• Try: Company Annual Report 2023

Tagging will tell a screen reader what kind of element it’s looking at – a headline, text, a picture or something that doesn’t need to be read at all.

You can check the tags within a PDF using the Adobe Acrobat Accessibility Check (see details further down this page). You can also check whether the PDF has tags by opening the Tags navigation pane by selecting:

1. View
2. Show/hide
3. Navigation panes
4. Tags

The structure of the tags will appear in the navigation panel. The message “No Tags available” is displayed if there are no tags.

You can automatically tag an untagged PDF document by selecting Add Tags to Document. You can also manually edit tags by using the Adobe Acrobat Reading Order tool.

You can add any missing alt text to graphics by selecting:

1. Tools
2. Accessibility
3. Set Alternative Text

You will see a window displaying information about the number of images in the PDF along with left and right arrows to help you navigate to them. Write alt text for each image in the text box. There is also an option to mark images as decorative. Once you’ve finished, press the Save & Close button.

Read our full alt text guidelines

Adobe Acrobat Pro can automatically check for many of the characteristics of accessible PDFs. You can choose which accessibility problems to look for and how you want the results reported.

1. In Acrobat Pro, choose Tools > Accessibility. The Accessibility toolset is displayed in the secondary toolbar.
2. In the secondary toolbar, click Accessibility Check. The Accessibility Checker Options dialog box is displayed.
3. In the Report Options section, choose how you want to view the results. You can save the results as an HTML file, or attach the results file to the document itself. Select a page range if you prefer to check individual pages of a document.
4. Select one or more of the Checking Options, and click Start Checking. The results are displayed in the Accessibility Checker panel on the left, which also has helpful links and hints for repairing issues.

The report displays one of the following statuses for each rule check:

• Passed: The item is accessible.
• Skipped By User: Rule was not checked because it wasn’t selected in the Accessibility Checker Options dialog box.
• Needs Manual Check: The Full Check/Accessibility Check feature couldn’t check the item automatically. Verify the item manually.
• Failed: The item didn’t pass the accessibility check.