Adobe Acrobat Pro: Complete PDF Document Accessibility Remediation

In order to ensure a PDF is as accessible as possible, it’s important to go beyond the Quick Fixes and check all aspects of a PDF document. For the most comprehensive run-down, see Adobe’s Create and Verify PDF accessibility documentation.
For those who do not have access to Adobe Acrobat Pro on their own computer, this software can be accessed through computers in the DiSCO.

What makes a PDF accessible?

• Searchable text
  • Unless this is an image-only PDF, the text should be searchable and use a font that allows for character extraction.
• Document structure tags
  • Possibly the most important part of an accessible PDF. Tags allow screen reader technology to find content by its hierarchical or semantic organization. 
• Proper reading order
  • The content reading order, based on tags and organization, should be checked.
• Alternative text
  • Images especially should have alternative text within the figure tag, to describe the image for those who are visually impaired.

Prevent security settings from interfering with screen readers:

It’s possible that the author has set an accessible PDF’s setting so that it can’t be copied, printed, extracted, commented on, or edited. However, this setting could interfere with a screen reader's ability to read the document. (Note: this will be flagged as an error in the accessibility report.)

To fix the rule manually: 

1. Select the hamburger menu (Windows) or the File menu (macOS) > Document properties.
2. In the Document properties dialog:
3. Select the Security tab.
4. From the Security Method drop-down, select No Security.
5. Select OK.

Image-only PDF

Reports whether the document contains non-text content that is not accessible. If the document appears to contain text, but doesn't contain fonts, it could be an image-only PDF file. However, some image-only PDFs can be converted to text using Optical Character Recognition (OCR).

To fix using OCR: 

Use OCR to recognize text in scanned images:

1. From the All tools menu, select Scan & OCR.
2. From the Scan & OCR panel, under Recognize Text, select In this file.
3. From the Pages dialog, select the pages you want to process, the document language, and then select Recognize text.

Tags

Tags make it possible to identify content type (such as headings, lists, images, tables, etc). Document accessibility is impossible without them! Fortunately, a properly formatted and exported source file will provide the best tags, and is much easier to do than creating them after the fact in Acrobat.

Tagging manually:

If tags are missing, you must create them:

1. First, create a Tags Root. This is necessary to create any other tags in the document. 
2. Select the Tags icon in the Navigation Panel on the right hand side of your screen. 
   
3. The Accessibility Tags menu will appear. If it indicates No Tags available:

• Click the ellipses to drop down the options, and click Create Tags Root. The word Tags will appear, indicating that there is now a tags root. 

Apply the following tags to your content using one of the methods Adobe provides — either by autotagging or by using the Reading Order tool (discussed in further detail below):

Common Tags

<P>        paragraph – normal text

<H1>         heading level 1 – main title of document

<H2>         heading level 2 – main headings in document

<Figure>    image – needs alt text

<L>        list – an ordered or unordered list

<LI>        list item – must be embedded within the <L> tag

<Link>        hyperlink – usually embedded within a <P> tag

Heading Tags and Their Uses

<H1>        Document title

<H2>        Main headings

<H3>        Subheadings

<H4>        Sub-subheadings

(Headings go all the way down to H5 and H6, for use with highly complex documents, but use sparingly!)

Tagging using “Autotag document”

With Autotag, Acrobat assesses its layout, structure and content to determine whether or not it can be read. 

While auto tagging can be a useful starting point for remediation, it WILL NOT produce an instantly accessible PDF on its own. You’ll need to manually verify the document is tagged correctly. 

In some cases, Auto Tagging will get you some of the way there, but in other cases, it will create such a mess that you’ll be better off starting from scratch, by first creating a Tags Root and then adding tags.

Tagging using “Logical Reading Order”

You can fix both reading order and basic tagging problems with the Reading Order tool.

NOTE: Save the document (or a copy of it) before you use the Reading Order tool, as undo-redo isn't supported for all operations. For more information, see Undo or redo the tag changes done using the Reading Order tool.

ALSO NOTE: The Reading Order tool is intended for repairing PDFs that were tagged using Acrobat (using the above methods), not for repairing PDFs that were tagged during conversion from an authoring application. Whenever possible, return to the source file and add accessibility features in the authoring application. This ensures that you don’t have to repeatedly touch up future iterations of the PDF in Acrobat.

Adobe has extensive documentation for using the Reading Order tool, which you should read if you need to check the logical flow of your tagged content. 

Adding Alt-text to Images

The easiest way to add Alt-text to images is by using the Add alternate text tool from the Prepare for Accessibility menu on the left hand side.

1. Click Add alternate text.
2. Now you can progress through all images in your pdf and either set alt text OR click Decorative figure for images that are only decorative.
   

• Decorative images, per the W3C, are images that “don’t add information to the content of a page. For example, the information provided by the image might already be given using adjacent text, or the image might be included to make the website more visually attractive."

Bookmarks

Bookmarks (optional) are a feature that allows for easy navigation to specific sections, pages, or content within a PDF document. They are especially useful in long or complex PDF documents, improving accessibility and user experience. 

Screen Reader Support

Bookmarks help those using assistive technology such as screen readers to navigate a PDF quickly, as they can jump directly to relevant sections of the document. 

Creating Bookmarks:

1. Navigate to the Bookmarks panel in the Navigation panel on the right side of the screen. 
2. Select the text or page you want to bookmark and click the Add a new bookmark button at the top of the Bookmarks panel (this looks like a bookmark with a + inside. 
3. Once you’ve created a bookmark, you may change its name and other attributes.