Identifying Table Headers


If a table in a PDF is missing identified headers, it will be listed in an accessibility report as a possible problem.  Tables that are used strictly to position content do not need headers identified.

Check if Table Contains Identified Header Cells

If a table was assigned header cells correctly in the source document (e.g. Word document), then when it was converted into a PDF, Adobe Acrobat will automatically assign a Table Header or TH Tag to table header cells.  Normally, when the option "Repeat as Header Row" is selected for header cells in a table in Word (see screenshot below), this assigns the TH tag.

Identifying table headers

You can check if tables within your PDF document contain TH tags by:

  1. Click on the TouchUp Reading Order tool.
  2. Locate the table on the page.
  3. Click on the number located in the upper left-hand corner of the item block (table).
  4. Click the button on TouchUp Reading Order window labeled Table Editor (In Adobe Acrobat 8 Pro, this option is called "Table Inspector.")  The table will be selected.  Rows and columns will be outlined.  The outlines may not match up to the table grid lines; this is okay.
  5. Right click (or ctrl-click for Mac users) the first header cell in the table and select Table Editor Options.

    Selecting Table Editor Properties.


    Selecting the "Show cell type (TH or TD) option from Table Editor Options Dialog box.
  6. The Table Editor Options window displays.  Under Label Option, select the check box next to the option "Show cell type (TH or TD)" (see screenshot at right).  What this does is automatically label cells in your table with a TH (Table Header cell) or TD (Table Data cell) indicating whether it is a header cell or a data cell.

 

 

 

Notice that the table colors for TH are red, and the TD cells are colored in black.  You can change these color assignments by editing them in the Table Editor Options Dialog box.

The table shows TH (table header) and TD (table data) labels depending on how the cells are tagged.

Identifying Column and Row Headers in a Table

  1. Click on the TouchUp Reading Order tool.
  2. Locate the content on the page that needs to be tagged correctly.
  3. Click on the number located in the upper left-hand corner of the item block (table).
  4. Click the button on the TouchUp Reading Order window labeled Table Editor (In Adobe Acrobat 8 Pro, this option is called "Table Inspector.")

    Selecting the Table Editor Option to edit table properties.


    The table will be selected.  Rows and columns will be outlined.  The outlines may not match up to the table grid lines; this is okay.
  5. Right click (or ctrl-click for Mac users) the first header cell in the table and select Table Cell Properties from the context menu (see screenshot below).

    Screenshot of Table Cell Properties option to begin assigning header cells to table.
  6. The Table Cell Properties window displays.  Under Type, select Header Cell.
  7. From the Scope drop-down menu, select Column if this is a column header cell.  If you are working with Row Heading cells, select a Scope of Row for the header cell.
  8. Click OK.  Follow this process for all the header cells in the table.

You can select several cells at a time by clicking on the first cell in the table > hold down the shift key on your keyboard > and click on the remaining cells you want to select until they are all selected.  Click the table cell properties option.  In this example (below), we would select all the table header cells and proceed to assign "header" as Type (in this example, headers are already identified for the table) and a Scope of "Column" and click the OK button.

Note: This option only works for cell value Types and not for Attributes, meaning you cannot use this to batch associate header id's to all cells in a column/row.

Assigning a Header Cell Type and Scope of Column for header cells in table.

Identifying Blank Table Header Cells Correctly

For Column or Row heading cells that are blank, mark these as Header cells for Type but select None for the Scope.

Video Tutorial - How to Identify and Work with Table Headers (4:30)

Adding a Table Summary

Adobe Acrobat also gives you the option of adding table summaries to your tables.  A table summary is equivalent to alternative text for an image in that it should be clear and concise in describing the table.  To create a table summary:

  1. Click on the TouchUp Reading Order tool.
  2. Locate the table and right click (or ctrl-click for Mac users) on the item block (table).
  3. From the menu, select Edit Table Summary.  The Table Summary box displays.
  4. In the Table Summary box, type a description.
  5. Click the OK button.

Video Tutorial - Adding a Summary to Your Table (1:33)

Associating Data Cells to Row and Column Headers

In addition to identifying Row and Column headers in your table, depending on the layout of the table, you may also need to associate data cells to row and column heders to facilitate the understanding and navigation of table content for users of assistive technology.  Screen readers will read table information from left to right, and a blind user can quickly lose track of what headers are related to each data cell in the table, especially if your table is formatted in a way that data cells are related to more than one header or if the table contains too much data.  Associating data cells to their corresponding header cells enables screen reading software to read the headers associated with the data cell before it announces the data cell content.  Please note that the Associated Header Cell feature is only available in Adobe Acrobat Professional version 9.

  1. Locate the table in your document and click on the number located in the upper left-hand corner of the item block (table).
  2. On the TouchUp Reading Order window, click the Table Inspector button.  The table will be selected.  Rows and columns will be outlined.  The outlines may not match up to the table grid lines; this is okay.
  3. At this point, you should have already identified the row and column headers in your table (see Identifying Column and Row Headers in a Table section above) from the previous step.  Now we will be adding IDs to column and row headers in order to associate data cells to these.
  4. Right click (ctrl-click for Mac users) on a column or row header cell in your table and select Table Cell Properties (see screenshot below).

    Screenshot of Table Cell Properties option.


    The Table Cell Properties dialog box displays.
  5. You will notice that the header cell has already been identified correctly under Type.

    Screenshot of Table Cell Properties dialog box. "Add an ID, then click the OK button."
  6. Under Attributes, in the ID field, enter a name that identifies the first column header of your table.  For this example, the row header is called '1' and stands for Week 1 of the semester.  We are going to identify it as "Week 1" and type this into the ID field.
  7. Click the OK button to save the ID for the column or row header.  Repeat this process for each column and row header.  These IDs will serve for the association process of data cells to row and column headers.
  8. After you have provided an ID for each column and row header, right click (ctrl-click for mac users) on the first data cell in your table and select Table Cell Properties.  Take note of the location of the cell and how it should be read to the user.

    Screenshot of Table Cell Properties option.
  9. On the Table Cell Properties dialog box, click the Add Table Header ID button.  The Add Table Header ID dialog box displays.

    Screenshot of Table Cell Properties dialog box with the Add Table Header ID option selected.
  10. From the Header ID drop-down menu, select the first row or column heading that should be associated with the data cell.  For my example, I will select "Week 1."
  11. Click the OK button.  The Table Cell Properties window re-displays (see next screenshot).









  12. The table header ID should now be displayin in the Associated Header Cells IDs box.

    Associated Table Header ID displays in the Associated Header Cell IDs box.



















  13. If there is more than one table header associated to a data cell in your table, for example, the data cell has a row and column header associated with it, you will need to click the Add Table Header ID button, select the Header ID from the menu list, and click OK.
  14. For our example, our data cell has the "Week 1" row header and "Topic" column header associated with it so these two header IDs now appear in the Associated Header Cell IDs box.

    Screenshot of the Table Cell Properties dialog box.  Add Table Header ID option is displayed - "Topic" is selected as the Header ID.


    Screenshot of the Table Cell Properties dialog box.  The Data Cell option is selected and "Topic" is selected in the Associated Header Cell IDs field.  "Two header IDs associated with a data cell."
  15. If you make a mistake and have added an incorrect Header Cell ID, you can remove it from the Associated Header Cell IDs box by clicking on the Remove Header Cell ID button.
  16. Click the OK button once you have associated all row and column headers to the data cell.
  17. Repeat these steps for all data cells in your table.  Remember, this process is most useful for tables in the which you may have more than one header cell (e.g. row and column header cells) associated to a data cell.
  18. When a screen reader like JAWS reads table cell, it will read the cells associated header cells and the content of the cell as well.  This allows for better understanding of the meaning of the data cell and its relationship to the table as a whole.

Video Tutorial - Associating Data Cells to Row and Column Headers (4:45)

Credits

  • This training has been funded in part by the EnACT (Ensuring Access through Collaboration and Technology) grant. 
  • Written and developed by Sacramento State Online Learning professionals, Monica Range and Cryssel Vera and technical crew, Ivan Vajar, Ken Young, and Jennifer Wicks with guidance from the CSU Professional Development Work Group.

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