If you haven’t already discovered it, Adobe has added enhanced tagging of PDF exports from InDesign files. InDesign now tags lists for the first time and more completely tags tables than in previous versions.
For me, list tagging is a big deal since I deal with technical research documents that frequently contain a large number of lists. In exports of tagged PDFs from previous versions of InDesign I always had to search out and manually tag lists in the tag tree of exported PDFs. In version 5.5, if I use the Bullets and Numbering formatting function to create paragraph style tags to format unordered and ordered lists, the resulting PDF has correctly tagged lists. This results in substantially less time spent in the overall process since it is a lot faster to use paragraph style tags created using the Bullets and Numbering function than it is to manually update a tag tree in a PDF for every instance of a list.
The Bullets and Numbering dialog is shown below. It is accessed from one of several locations including the Paragraph Style palette and the Paragraph palette. Use this dialog to format all lists that you want properly tagged when exported to a tagged PDF.
The other tagging enhancement added with this version of InDesign is to tables. Previous versions of InDesign partially tagged tables if you used the Table function to build your tables. Version 5.5 takes the table tagging further, but still leaves some manual work to be done in Acrobat. The column heads are now properly tagged <TH> denoting a heading rather than as <TD> denoting data. Row heads are not tagged, and still must be manually corrected in the tag tree. The scope of the table cell is not identified for either the column head or row head cells and also must be set. A sample of a simple table is shown below.
In order to properly identify the column header row in InDesign, the table should be created using the Insert Table dialog that properly identifies any header rows as shown in the Insert Table dialog below. If you are working with a table created without designated header rows, it can be corrected using Table Options > Table Setup… under the Table menu.
If the header row is designated, the table in the exported PDF will be properly tagged as shown in the tag tree below.
Note the structure of the tag tree. I shows the child tags of <THead> and <TBody> to correctly identify the heading rows and the body rows of the table. Note that the column heads are tagged as <TH>, denoting a heading cell versus the <TD> denoting data cells. The table still requires editing to identify row heads as <TH> rather than <TD> and to properly identify the scope of the heading cells for both column and row heads. The easiest way to complete the tagging in Acrobat Pro is to use the Table Editor which can be found on the Touch Up Reading Order dialog, as shown below.
After selecting the table to be edited, click on the Table Editor button on the Touch Up Reading Order dialog. Then select each of the column heading or row heading cells to be corrected (you can shift click to select multiple column head or row head cells), right click on any selected cell to bring up the option menu, and select “Edit cell properties…” This brings up the Table Cell Properties dialog as shown below.
If it is not already selected, select the Header Cell radio button under Type and then designate either Column or Row for Scope. Note that for spanning column heads, you can also designate the number of columns spanned for Column Span.
For further information on how to use the Table Editor to repair tables in Acrobat Pro review the PDF Techniques for WCAG 2.0 at W3C site relating to the Table Editor http://www.w3.org/WAI/GL/WCAG20-TECHS/pdf.html#PDF20 or review DHHS detailed instructions on editing table tags at http://www.hhs.gov/web/508/tabletags.html.