What is an Accessible PDF?

It’s not just good business to publish accessible and usable digital documents for customers using assistive technologies. It’s the law. The trouble is – it’s just not that simple to build accessibility features into all your documents. Even if you do understand all the requirements, manually adding accessibility features can be prohibitively time-consuming.

For example, a PDF can be a simple, single-page text document with headings, sub-headings, and body text that is easy to include the appropriate metadata and tags to ensure accessibility. But a PDF can also be a complex, multi-page report with images, tables, graphs and graphics that require alternate descriptions and sophisticated tagging to be accessible by assistive devices. Then there are PDF forms that have even more specialized accessibility requirements to ensure all users understand what information is required on each line or in each box.

Let’s start at the beginning

There are nine broad categories of accessibility features that are essential to meeting the requirements of Section 508, WCAG 2.1 and PDF/UA guidelines. Each category has several elements that could impact the accessibility and usability of your documents. The purpose of the guidelines is to allow users of assistive technology to:


Make use of PDF documents without assistance from others.

Reach a specific goal easily, directly and within a reasonable time frame.


Have the same-quality experience using PDF documents as people without disabilities.

Descriptions of the nine categories of accessibility features are shown below. The U.S. Department of Health and Human Services has published a comprehensive PDF File 508 Compliance Checklist with references to the relevant WCAG 2.0 guidelines if you’d like to view all the categories and subcategories that affect PDF accessibility.


Elements of an Accessible PDF

1. General PDF Properties (metadata)

The title and description of the document must be shown in the properties menu of the document. The document should also include proper tagging, bookmarks, selection of the primary language and a host of other properties in place.

2. Color

Information must be conveyed in ways other than just by the use of color, and text must have a contrast ratio of 4.5:1 or greater.

3. Links

Links must be tagged correctly, distinguished by more than just a contrasting color, and link text must be understandable out of context of the page.

4. Images

Images need to be tagged for proper order within the content or tagged as an artifact or background when applicable. Alt text must provide the same understanding of the image that a visual user would have. In addition, an accessible PDF should not have any images that portray text that is meant to be read by a visual user.

5. Tag Structure

The tag structure tells the screen reader the order to read the document. Therefore, it must provide the same, logical reading experience as a visual reader. Tagged non-standard text like glyphs, footnotes and endnotes, foreign words and more must flow in the logical reading order of the document.

6. Tables

Table tags, including header and cell tags, are essential to ensure a screen reader can read the table and present the information in an understandable way. The table tag tree must match the visual table layout.


7. Lists

List tags are also essential to ensure the screen reader can correctly decipher all the elements of the list and present them in the proper reading order.

8. Headings

Heading tags help delineate sections of text. Without heading tags, there are no breaks in the content, making it all run together.

9. Forms

Form field tags, labels and tool tips are essential, along with clear instructions about required fields. 

As you can see, it’s not that easy to make sure all the accessibility requirements are in place for every digital PDF document you publish. The Open Access Technologies team is ready to work with you to navigate the requirements of Section 508, WCAG 2.1 and PDF/UA to make sure your digital documents meet the applicable requirements for your industry. Let’s get started today.

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