PDF Accessibility Guide

Remediating PDFs for accessibility is a lengthy process, which is why we generally recommend using other formats if possible. In some instances, PDF must be used (the document is designed for print publication, legal reasons such as tax forms, or time constraints prevent good conversion to HTML). In these cases, Adobe Acrobat Pro contains an accessibility checker that can check most accessibility issues. The complete process is laid out in Acrobat Pro’s documentation on Creating and Verifying PDF Accessibility. Remember that using the Accessibility Checker tools does not guarantee that a PDF will be accessible and some accessibility issues will need to be checked manually. In particular pay attention to checking the tags and reading order. Sometimes, the accessibility checker will pass content that is not actually accessible.

Heading levels should be organized hierarchically, just as in a topic outline. Heading 1 is usually reserved for the page title. Heading 2 is used for all subtopics on the page, Heading 3 for sub-subtopics, and so on.

It’s often easiest to structure headings correctly in an authoring application such as Word and then convert it to a PDF. Acrobat should retain the heading tags when you convert the document. See How Do I Create Accessible Headings in Word. Otherwise, you can add them to your PDF with the Acrobat tagging process.

To add heading tags to your PDF text:

1. Click All tools in the top left corner to open the Tools list.
2. Scroll down the list and choose Prepare for accessibility.
3. Click on Automatically tag PDF.
4. When the process is complete, check the tags for accuracy. To see how the document has been tagged, click on the tag icon in the right-hand menu.
5. Click on any <H> tags in the Accessibility tags window to see which text has been tagged as a heading.
6. If anything needs to be changed, double click the <H> and type in the appropriate tag.

Additional Information

• Adobe Acrobat: Creating accessible PDFs (scroll down to Tag the PDF)
• To learn more about why logical structure is important to visually impaired users, visit WebAIM’s Headings.

Checking that Lists are Tagged appropriately in Adobe Acrobat Pro

To check that a list is tagged appropriately in a PDF:

1. Click Accessibility Tags in the side panel. If Accessibility Tags is not visible right click to access side panel options and select Accessibility Tags.
2. Locate the appropriate tag for the list. The list should be tagged as <L>. Select the list and expand it by clicking on the arrow before the list. Each item in the list should have its own List item tag <LI>.
3. When that List item tag is expanded each List item should contain a Label <Lbl> that contains the bullet point or number and a List Body <LBody> that contains the text of that List item.
4. Manually verify that each element of the list is correctly tagged.

If the list is not tagged appropriately, it is easiest to return to the original source document and remediate any problems there. Once any issues have been resolved, re-export the document into PDF and verify that the problem is resolved.

Manually Tagging Lists in Adobe Acrobat Pro

If you need to manually create a missing list tag in a PDF, a new list tag can be added by opening the Accessibility Tags side panel and right clicking on the element directly before where you would like to insert the list. Select New Tag and choose the list tag <L>. Following the same steps as above, create List Item tags <LI> within the new list tag for each bullet or number of the list. Make sure the List Item tags are appropriately nested in the List tag. If not drag and drop them into the List tag.

At this point, the List Item tags are empty and the missing list elements need to be manually added. In order to add these missing elements (such as labels and list items):

1. Use the Reading Order Panel to manually select the element that needs to be tagged.
2. Initially just mark the new element as “Text/Paragraph” to generate a new <P> tag for that element.
3. Open the Accessibility Tags side panel. Right click the <P> tag from the last step, select Properties and change the tag type to either a Label <Lbl> or List Body <LBody>.
4. Make sure each list element is properly nested within the List tag. Elements can be dragged and dropped into the appropriate place.  

The provided link text needs to give sufficient information about where the link leads. Phrases such as “click here” or “read more” do not give sufficient information about the link destination out of context. Raw URLs pose problems for both screen reader users and voice input users because raw URLs are difficult to understand and pronounce.

Check Links in PDFs

Links in pdfs need to be manually verified that they lead to the proper location. If a link is ambiguous or unclear, it is easiest to go back to the source document and edit the link there.

The Link tool in the Edit tab can be used as a last resort to delete or add new links as necessary. 

For alt text to be accessible, it must convey the content and context of the image.

If a graphic element is there simply for decorative purposes, it does not need alt text and can be marked “Decorative.” See Add alternative text to a shape, picture, chart, SmartArt graphic, or other object and scroll down to “Mark Images as Decorative.”

A Note on PDFs

PDFs generally are not a very accessible format, and we generally recommend PDFs only be used when no other alternative is available. When PDF is the only available format, you will need to use Adobe Acrobat Pro to check and remediate accessibility issues in your PDFs (Adobe Acrobat Pro is available for free for faculty, staff, and students at the Webstore).

Adding Alt Text to a PDF

1. In All Tools scroll down to Prepare for Accessibility (select More at the bottom for the full list).
2. After selecting Prepare for Accessibility, click Add alternate text.
3. Write/edit alt text that describes the content and context of each image.  

Additional Information

• To learn more about why accessible images are important to visually impaired users, visit WebAIM: Accessible Images.
• To learn more about the importance of alternative text, visit WebAIM: Alternative Text or Microsoft: Everything You Need to Know to Write Effective Alt Text.

It’s often easiest to structure tables correctly in an authoring application such as Word and then convert it to a PDF. Acrobat should retain the table structure when you convert the document. Otherwise, you can add them to your PDF with the Acrobat tagging process. To fix any tags for table cells that were not labeled correctly.

Editing table headers <th> and table data <td> in Adobe Acrobat Pro

1. Select the Reading Order tab in the Accessibility Toolbar.
2. Select that table you want to remediate and then open the Reading Order window.
3. Select Table Editor.
4. Select the cell that needs to be edited.
5. Right-click and select Table Cell Properties.  

The Accessibility Checker in Adobe Acrobat Pro does not check for color contrast. The accessibility checker will always return “Needs manual check” under the Color Contrast section of an accessibility report. Color contrast can be manually checked with tools like WebAIM’s Color Contrast Checker. To meet WCAG 2.0 level AA requirements, the contrast ratio must be at least 4.5:1 for normal text and 3:1 for large text.

If there are any areas in the document that need to be adjusted, we recommend returning to the original file (Word, PowerPoint, etc.) to fix the error.

How to Use WebAIM’s Color Contrast Checker

1. Open WebAIM’s Color Contrast Checker.
2. Use the tools under the Foreground section to enter your text color. You can use a hex code, RGB value, or use the eye dropper tool to sample your text color.
3. Use the tools under the Background section to enter the background color.
4. Check the report below to ensure that your document content meets WCAG AA guidelines.

If you use the Eye Dropper Tool to sample your document colors, be sure that you select a pixel from the center of the character. This will give you the best sample for the font color. Pixels near the edge of a character will not be an accurate representation of the font color.  

Additional Information

• For more information see WebAIM’s Contrast and Color Accessibility.
• For documentation, see Adobe Acrobat User Guide.

Passages in another language must be defined within the document so the screen reader adjusts to the pronunciation and reading order of that language.

A Note on PDFs

PDFs generally are not a very accessible format, and we generally recommend PDFs only be used when no other alternative is available. When PDF is the only available format, you will need to use Adobe Acrobat Pro to check and remediate accessibility issues in your PDFs (Adobe Acrobat Pro is available for free for faculty, staff, and students at the Webstore).

How to Update the Language Settings

To check Document Language:

1. Under File select Properties.
2. In the Properties dialog select Advanced.
3. Select the correct language from the dropdown named Language in Reading Options. 

To define a short passage in another language:

To change a single elements language, the element will need to be selected in Accessibility tags. To access Accessibility tags:

1. Select the Overflow Menu (Windows) or View (MacOS) and then select Show/Hide > Side Panels > Accessibility Tags.
2. In Accessibility tags locate the element whose language needs to be changed.
3. Right click the element and select Properties.
4. Choose the correct language from the Language dropdown menu. Close automatically saves changes. 

Limitations to the Accessibility Checker

If the PDF fails multiple categories in the Accessibility Checker, the most efficient way to remediate the PDF is to correct accessibility issues in the original source file. If possible, avoid using PDF and distribute the file as a Word document or other more accessible format. If using a PDF is necessary, reconvert the document to PDF and run the accessibility checker again. Any remaining issues can be directly fixed in Adobe Acrobat Pro.

Current shortcomings of the Adobe Acrobat Pro Accessibility Checker:

• Tags need to be manually verified and changed to properly reflect headings, lists, tables, and other objects as necessary.
• Reading order and tag order need to be manually checked.
• Color Contrast must be manually checked.
• Document tags such as language and all hyperlinks need to be manually checked.

Accessing the Accessibility Checker

1. In the All tools menu, select Prepare for accessibility.
2. In the Prepare for Accessibility pane, select Check for accessibility.
3. In the Accessibility Checker Options window, select Start Checking (after verifying the file location for the generated report).
4. Running Start Checking generates the report and opens the Accessibility Checker on the right hand of the screen.

The report will highlight major issues that need to be addressed. Remember that the accessibility checker does not address every issue and some things will need to be verified manually. 

Additional Information

For a basic overview, see the Acrobat tutorial on remediating an inaccessible PDF.

• TPGI Color Contrast Analyzer (CCA)
• Convert an Image-only PDF with Text Recognition in Adobe Acrobat Pro
• Adobe Acrobat Accessibility Training Resources
• Adobe Acrobat Accessibility
• Accessing PDF Documents with Assistive Technology: A Screen Reader User's Guide