Adobe Acrobat XI - Manual (Page 462)

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Accessibility, tags, and reflow
Last updated 1/14/2015
Check and add alternate text for figures
If you want screen readers to describe graphical elements that illustrate important concepts in a document, you must
provide the description using alternate text. Figures aren’t recognized or read by a screen reader unless you add
alternate text to the tag properties. If you apply alternate text to text elements, only the description, not the actual text,
is read.
1 Select the Touch Up Reading Order tool.
2 Select Show Tables And Figures in the dialog box.
3 Right-click the figure, and choose Edit Alternate Text from the pop-up menu.
4 In the Edit Alternate Text dialog box, type a new (or edit an existing) description for the figure, and then click OK.
Edit table tags and tag unrecognized tables
Tables pose a special challenge for screen readers because they present textual or numerical data to be easily referenced
visually. Content within table cells can be complex and might contain lists, paragraphs, form fields, or another table.
For best results when tagging tables, use the application that you created the document with to add tags when you create
the PDF. If a PDF isn’t tagged, you can add tags by using the Add Tags To Document command. Most tables are properly
recognized using this command; however, the command may not recognize a table that lacks clear borders, headings,
columns, and rows. Use the Touch Up Reading Order tool to determine if the table has been properly recognized and
to correct recognition problems. To add specialized formatting to tables and table cells, use the Tags panel.
You can use the Table Editor to automatically analyze a table into its components and apply the appropriate tags, but
you may still need to check and correct some of these tags manually. By viewing table tags, you can determine whether
columns, rows, and cells have been correctly identified. Tables that lack well-defined borders and rules are often tagged
incorrectly or contain adjacent page elements. You can correct poorly tagged tables by selecting and redefining them;
you can split combined cells by creating a tag for each cell.
To correct complex tagging problems for tables, you often must use the Tags panel.
1 Select the Touch Up Reading Order tool, and then click Show Tables And Figures.
2 If the table isn’t clearly labeled in the document pane, drag to select the entire table, and then click Table in the dialog
box.
3 Click Show Table Cells to make sure that all cells in the table are defined as individual elements.
4 If cells don’t appear as separate elements, do one of the following:
• If one or more cells are merged, use the Touch Up Reading Order tool to select the area within a single cell, and
then click Cell in the dialog box. Repeat for each merged cell.
• If cells aren’t highlighted, the table might not use standard table formatting. Re-create the table in the authoring
application.
5 If the table contains cells that are intended to span across two or more columns, set ColSpan and RowSpan attributes
for these rows in the tag structure.
Remove or replace document structure tags (Acrobat Pro)
If adding tags to a PDF in Adobe Acrobat results in a tagging structure that is overly complicated or too problematic to
fix, you can use the Touch Up Reading Order tool to remove or replace the current structure. If the document contains
mostly text, you can select a page and then remove headings, tables, and other elements to create a cleaner, simpler
tagging structure.
Acrobat can retag an already tagged document after you first remove all existing tags from the tree.