Tagging is essential for PDF accessibility. Tags establish logical reading order and to provide a means for indicating structure and type, adding alternative text descriptions to non-text elements and substitute text (referred to as actual text) for elements in the PDF document.
If you’ve followed each step so far, your PDF document is searchable either from optical character recognition or through the native document conversion. Any desired interactivity has been added in the form of navigational controls or interactive form fields. The next step is to add tags to the document if it has not been tagged. This section addresses the addition of tags, while “Step 7: Examine and Repair the Tag Structure” explains how to fix tags and properly tag complex layouts and elements.
Note: If the PDF document has been tagged, skip this discussion and proceed to “Step 7: Examine and Repair the Tag Structure”.
There are several ways to determine if a PDF file has been tagged:
View Document Properties
- Open the Document Properties dialog: File > Properties.
- Look for the “Tagged PDF” label in the lower left hand corner of the Description tab (See “Figure 11. Tagged PDF File Property”).
Reveal the Tags Panel
- Open the Tags panel.
Select View > Show/Hide > Navigation Panes >Tags.
- Examine the Tags panel.
- A tagged document will show tags and a structure tree descending from the root node. To fully expand the entire tree, Control + click on the root node labelled “Tags” (See “Figure 12. Tags Panel Structure Tree Showing Tags”).
- An untagged document will display the words “No Tags Available” as its root and no structure tree will appear (See “Figure 13. Tags Panel with No Tags Available”).
In some cases, a document may not be considered tagged by Acrobat even though a structure is visible in the Tags panel. To indicate the document is tagged (See “Figure 14. “Document is Tagged PDF” Indicator in a Structured Document”):
- Select the Options icon from the Tags panel.
- Ensure the “Document is Tagged PDF” option is checked.
Run the Accessibility Checker
The Accessibility Checker can perform a thorough check for many common accessible issues found in PDF documents, including missing tags. For a complete guide on using the Accessibility Checker in Acrobat please refer to the document “Acrobat DC Access Checker”. The section below will only specifically address using the checker to determine if tags are missing.
To run the Accessibility Checker to determine if the document is tagged, perform the following:
- Display the Accessibility Pane: In Adobe Acrobat Pro DC, the Accessibility tool pane is not shown by default.Select View > Tools > Accessibility from the Adobe Acrobat Pro DC menu to show the pane.
- Select the Full Check command from the Accessibility pane: Selecting the Full Check command opens the Accessibility Full Check dialog (See “Figure 16. Acrobat Pro DC Accessibility Checker Dialog”).
- Choose how you would like the results displayed: The results can be saved as an HTML file, or as comments placed where the accessibility problems are detected.
- Select a page range if a check is needed for individual sections of a document.
- Choose the items you want to test from the four categories in the drop-down menu (Document; Page Content; Forms, Tables and Lists; and Alternate Text and Headings).
- Select the Start Checking button.
The results are displayed in the Accessibility Checker panel in a tree format, which allows the user to navigate through each error the Checker encountered. (See “Figure 17. Acrobat Pro DC Accessibility Checker Panel”). Note the areas under Document, Page Content, and Forms, Tables and Lists that are related to tags. (See “Step 9: Use the Accessibility Checker to Evaluate the PDF File”).
Use the Touch Up Reading Order Tool (TURO)
Another way to check for the presence of tags is to display the Touch Up Reading Order tool or TURO. To display the Touch Up Reading Order tool, if the Accessibility panel is not already on display, select Tools > Accessibility from the Adobe Acrobat Pro DC menu. Then select the Reading Order command under the Accessibility panel (See “Figure 18. Displaying the Touch Up Reading Order Tool”).
A tagged document will display shaded areas on the page that are numbered (See “Figure 19. Viewing a Tagged Document with the Touch Up Reading Order Tool”). An untagged document will not display these numbered rectangles (See “Figure 20. Viewing an Untagged Document with the Touch Up Reading Order Tool”).
Tags can be added to untagged documents using Adobe Acrobat Pro DC. There are several ways to do this:
- Add Tags from the Make Accessible Action Wizard
- Add Tags from the Accessibility Checker results
- Add Tags Manually via the Tags panel
Add Tags from the Make Accessible Action Wizard
- Open the Make Accessible Wizard
- Activate the “Autotag Document” command to add tags to the document.
- Verify the tags in the Tags panel.
Add Tags from the Accessibility Checker Results
When the document is not tagged at all, “Tagged PDF” will be listed as “failed” under the Document tree item. To add tags to the document:
- Right click or press the applications key (Windows) on the “Tagged PDF—Failed” tree item
- Choose Fix
- Verify tags have now been added to the document in the Tag panel. The “Tagged PDF” item will be listed as “passed” under the Document tree.
When the document was tagged but specific content is still missing tags:
- Select “New Tag” from the Object tool in the Tag panel.
- Select the type of tag from the New Tag dialog and select OK
- Move the new tag to the location in the Tag tree where the content is missing.
- Highlight the missing object in the document pane.
- Right-click on the new tag in the tree structure
- Choose Create Tag from Selection (See “Figure 22. Create Tag from Selection Context Menu Item”).
Note: It is useful to check the “highlight content” context menu item shown in Figure 17 "Create Tag from Selection Context Menu Item" above. This option will highlight the corresponding item from the tag tree in the document pane with a blue rectangle.
Add Tags Manually via the Tags Panel
With the Tags panel open, select “Add Tags to Document from the Options button, or with the Accessibility panel open in the Tools pane, select the “Add Tags to Document” command (See “Figure 23. Adding Tags to an Untagged PDF File”).
If Acrobat encounters potential problems while adding tags to the document, the Add Tags Report opens in the navigation pane. The report lists potential problems by page, provides a navigational link to each problem, and offers suggestions for fixing them. This is similar to the Accessibility Checker Report that is produced when an accessibility full check is run as described in “Step 9: Use the Accessibility Checker to Evaluate the PDF File”.
Remember that the automatically generated Recognition Results report requires human intervention to determine the best solution. For example, the report might state that an element has been tagged as a figure and requires alternate text to make it accessible. However, that figure may be a background design element that doesn’t convey any meaning to the user.
Note: The Add Tags Report highlights tagging-related problems only, and it is a temporary file that cannot be saved. Other accessibility issues, including reading order, can be assessed by using the Accessibility Checker.
Adding tags to a PDF may result in a tag structure that is overly complicated or problematic to fix manually. Specific tags can be removed directly via the Tags panel or via the Touch Up Reading Order tool. When a layout table is used, for example, the tagged table structure should be removed to create a cleaner, simpler tagging structure.
Proceed to Step 7: Examine and Repair the Tag Order.