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Creating Accessible PDFs with Adobe Acrobat Professional

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Constructing Accessible Tables

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Often tables are used in two ways: for layout purposes and to organize and display associated data. The use of layout tables should be limited. Layout tables can cause navigational issues for AT users. Layout tables should not contain data table structure, such as table header (TH) tags, for headers.

There are two types of data tables: simple and complex. Simple data tables have a one-column header to one-row header ratio. Complex data tables have two or more levels of row and/or column headers that must be associated to make sense. The following are some important keys to creating accessible data tables in Adobe Acrobat PDF documents:

  • Ensure data tables are formatted using table elements.
  • All data tables should use TH tags to identify header cells.
  • Define column headers across page breaks.
  • Associate table row and column headers with data cells.
  • Place content that is in separate rows and columns into separate data cells.
  • Merged row and column headers need to have RowSpan or ColSpan defined.

Table Structure

Using the below example of a three-column, two-row table, the structural elements and nesting of tags can demonstrate what the final proper structure of a table needs to appear as in the Tags pane.

Example Table:

Header 1 Text

Header 2 Text

Header 3 Text

Row Header Text

Column 2, row 2 data cell text

Column 3, row 2 data cell text


Example tag structure:Tag structure of an example table in the tags pane

  • <Table> - Element definition, a table.
    • <TR> - Table Row
      • <TH> - Defines a table header cell
        • Header 1 text
      • <TH> - Defines second column header cell
        • Header 2 text
      • <TH> - Defines third column header cell
        • Header 3 text
    • <TR> - Table Row
      • <TH> - Defines the row header cell
        • Row header text
      • <TD> - Defines a table data cell
        • Column 2, row 2 data cell text
      • <TD> - Defines a table data cell
        • Column 3, row 2 data cell text

Other imperative structural modifications will not be visible in the Tags pane or within the table itself, but they are crucial in order for AT users to navigate and comprehend data table information. There are several steps involved to properly structure tables and associate data cells with table headers. To simplify the process, some step-by-step instructions have been provided in the simple tables, complex tables and spanned cells sections.

Getting Started with the TouchUp Reading Order Tool

The TURO tool can help get the table structuring process started. Further work will need to be done in the table editor and/or Tags pane to complete the process.

One of the ways the TURO tool can help is if a table in the document has implicit structure. Sometimes instead of using proper table structure, tabbing or other kinds of spacing are used to visually imply a table, but AT users have no way to discern what information is related to one another.
Example of what an implicit table may look like
An implicit table will most likely be contained in Paragraph (<P>) tags in the Tags pane instead of the proper Table (<Table>) and associated tags. The TURO tool can get the basic structure inserted into the tags and mapped to the proper elements so that the object will be recognized as a table by AT.

  1. Navigate to and open the Tools pane.
  2. Locate and expand the options under Accessibility.
  3. Navigate to and activate the TURO tool.
  4. Confirm the TURO dialog appears.
  5. Select the content in the document that needs to have table structure applied.
  6. Navigate to and activate the Table button in the TURO dialog.
  7. Confirm an X appears over the content and the word Table is placed in the upper left corner of the object.
    Implicit table now a structured table after using the TURO
  8. Locate the table content in the Tags pane and confirm there are table structure tags present.

 

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