If the tags in a PDF file in Acrobat appear to be overly complicated and cannot be managed, it is possible to re-tag an already tagged document. To do this, first remove all existing tags from the tree. Use the Touch Up Reading Order tool to remove or replace the current structure. If the document contains mostly text, select a page and then remove headings, tables, and other elements to create a cleaner, simpler tagging structure.
The Touch Up Reading Order tool is very useful to create tags in untagged PDFs or to add new tags to an existing tagged structure, but the Add Tags to Document command provides more detail. For example, tags such as paragraphs, bulleted and numbered lists, line breaks, and hyphens are available from Add Tags to Document. Before clearing the existing structure, make sure that manual tagging is the only recourse.
To remove the tags from the entire PDF document, do the following:
This process works best in pages that contain a single column of text. If the page contains multiple columns, each column must be selected and tagged individually.
To perform more advanced reading order and tagging tasks—such as tags table of contents, adding replacement (actual) text for blocks of text, removing obsolete tags, and adding replacement (actual) text to links—it may be necessary to use the Content panel and the Tags panel, which provide an advanced set of tools and features for manipulating PDF tags. The Touch Up Reading Order tool generally changes and synchronizes both of these panels, but the two can become out of sync.
Use the Content panel to correct reflow problems in a PDF that cannot be corrected by using the Touch Up Reading Order tool. Take note that it is easy to damage a PDF by editing content objects as removing a content object will remove the object from the visual page. Be familiar with the PDF structure before changing anything. For comprehensive information about PDF structure, refer to the PDF Reference First Edition: Adobe Portable Document Format Version 1.7, on the PDF reference page (English only) of the Adobe website.
The Content panel provides a hierarchical view of the objects that make up a PDF, including the PDF object itself. Each document includes one or more pages, a set of annotations (such as comments and links), and the content objects for the page, consisting of containers, text, paths, and images. Objects are listed in the order in which they appear on the page, similar to tags in the logical structure tree. However, objects in the Content panel do not require tags to view or change the object structure.
To display the Content panel, choose View > Show/Hide > Navigation Panes > Content from the Acrobat DC menu.
Click the plus sign (+) (Windows) or the triangle (Mac OS) next to the document name to view each page content entry. Control + click expands the entire content tree. The Content panel provides an option to show the corresponding tag in the Tags panel by activating the context menu and choosing “Show in Tags Panel”.
Containers or objects can be moved by selecting them and doing one of the following:
Drag it to the desired location.
Figure 34. Set Highlighting On for the Content Panel
In the Content panel, use the Options menu or right-click an object to choose from the following options:
The Tags panel allows the viewing and editing of tags in the logical structure tree, or tags tree, of a PDF file. Tags in panel appear in a hierarchical tree order that indicates the reading sequence of the document by assistive technologies such as screen readers. The first item in this structure is the Tags root. All other items are tags representing standard PDF structure elements and are children of the Tags root. Tags use coded element types that appear in angle brackets (< >). Each element, including structural elements such as sections and articles, appear in the logical structure order by type, followed by a title and the element’s content or a description of the content. Structural elements are typically listed as container—or parent—tags and include several smaller elements—or child tags—within them. The tag description is not seen by users of assistive technology and can be used by the author to provide comments during the tagging process.
Many tagging issues can be corrected by using the Touch Up Reading Order tool, but it is necessary to use the Tags panel to address detailed tagging of tables and substructure items—such as paragraphs, lists, and sections that require multiple languages. First consider using the Autotag Document feature and the Touch Up Reading Order tool and then use the Tags panel to modify the tags.
To display the Tags Panel Choose View > Show/Hide > Navigation Panes > Tags.
Figure 35: Toggle Content Highlighting On/Off for the Tags Panel
There are many actions that can be taken on a tag within the Tags panel. These include but are not limited to:
To reveal the Object Properties (See “Figure 36. The Object Properties Dialog: Tag Tab”) for any tag, select the desired tag in the Tags panel and perform one of the following:
Figure 36: The Object Properties Dialog: Tag Tab
From the Tags panel:
From the Tags panel:
From the Tags panel:
In the Tags panel, use the Options menu or right-click a tag in the logical structure tree to choose from the following options:
From the Tags panel:
When tags are added to a PDF that includes comments, the comments are tagged as well. However, if comments are added to a PDF that’s already tagged, comments are untagged unless comment tagging is enabled first.
If a document contains untagged comments, they can be located in the logical structure tree and tag them by using the Find command in the Tags panel.
Links and form fields should have already been added to the document with the appropriate tags if the previous steps in this document were followed. However, if the form fields or links were already present and tags already existed in the document, use the following steps to make the form field or link accessible. It is NOT enough to simply place the content under a link or form tag in the tags tree -- an appropriate object tag must also be present as a child of the parent link or form tag in the tree along with the corresponding text node.
From the Tags panel:
When a language is set for an element in the tag tree that language applies to all content under the tag. If the different language is part of the same tag it must first be split out into a separate tag. An easy way to do this is to create a new Span tag below the current element and then arrange the text content under the current tag in the appropriate location.
To set the language:
Proceed to Step 8: Add Alternative Text.