Accessible PDF Documents

What makes a PDF accessible?

Creating an accessible PDF ensures that all users can read and navigate your document effectively, including individuals with disabilities who rely on assistive technologies such as screen readers, magnifiers, or braille displays. Accessibility in PDFs improves usability and helps organizations comply with legal standards like WCAG (Web Content Accessibility Guidelines) and Section 508 standards.

Core Components of an Accessible PDF

1. Searchable and Selectable Text
   • Accessible PDFs must have text that can be selected, searched, and read by assistive technologies. Scanned documents that are stored as images of text need Optical Character Recognition (OCR) to convert them into real text. 
2. Logical Reading Order
   • The content must follow a logical order, ensuring that it is read in the correct sequence by screen readers. This includes headings, body text, and lists arranged hierarchically in a meaningful way.
3. Proper Use of Tags
   • Tags are the backbone of an accessible PDF. They provide structure to the document by defining elements such as:
     • Headings (<h1>, <h2>) to indicate hierarchy.
     • Paragraphs (<p>) to define text blocks.
     • Lists (<ul> and <ol>) for ordered and unordered lists.
     • Tables to associate headers with data cells, ensuring users can navigate and understand data effectively.
   • Tagging Benefits: Tags allow screen readers to interpret and vocalize the content accurately, making it accessible to users with visual impairments.
4. Alternative Text for Images
   • Non-text content like images, charts, and graphs must have alternative text (alt text) to describe their purpose and meaning. For example:
     • For a chart: "Bar chart showing sales growth from 2020 to 2024."
     • For a decorative image: Mark it as "artifact" or "decorative" so it is ignored by assistive tools.
5. Sufficient Color Contrast
   • Ensure that text contrasts adequately with the background to meet WCAG standards (minimum contrast ratio of 4.5:1 for body text).
   • Why It’s Important: Users with low vision or color blindness need strong contrast to distinguish text.
6. Descriptive Links
   • Hyperlinks must include meaningful and descriptive text, rather than generic phrases like "Click here." For example:
     • Instead of “Click here,” use: “Learn more about accessibility guidelines.”
7. Accessible Forms
   • Interactive PDFs with forms must include:
     • Labels for every form field, such as "First Name" or "Email Address."
     • Keyboard Accessibility: Users should be able to tab through form fields without a mouse.
     • Error Notifications: Provide clear instructions when users fill out forms incorrectly.
8. Navigation Features
   • PDFs must include navigation tools such as:
     • Bookmarks: Allow users to jump directly to specific sections.
     • Table of Contents: Acts as a roadmap to the document's structure.
     • Page Numbers: Add page numbers to help users orient themselves.
9. Metadata and Document Properties
   • Accessible PDFs should have proper metadata, such as:
     • Title: A clear and descriptive title of the document.
     • Author: The creator of the document.
     • Language Settings: Specify the document's language (e.g., English, Spanish) to help screen readers pronounce the text correctly.
10. Tables and Data Accessibility
    • Tables must be structured correctly:
      • Use <th> (table headers) to define column and row headers.
      • Avoid merging cells unnecessarily, as it complicates navigation for screen readers.
11. Multimedia Accessibility
    • If the PDF includes audio or video, it must:
      • Provide captions for videos and transcripts for audio.
      • Include accessible controls for multimedia playback.
12. Compatibility with Assistive Technologies
    • Accessible PDFs must work seamlessly with tools like:
      • Screen Readers: JAWS, NVDA, or VoiceOver.
      • Magnification Tools: ZoomText or built-in magnifiers.

 

Accessible PDFs include but are not limited to the following characteristics:

• Searchable text
• Other interactive features — hyperlinks and navigational aids
• Document language and title indication
• Security that will not interfere with assistive technology
• Document structure tags and proper reading order
• Alternative text descriptions for non-text elements

Learn more about creating accessible PDFs in the Accessible PDF Document Guide.