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Text-only Version.

Checking Your PDF for Accessibility

WAC Workshop. February 2005.Written and Presented by: Lori Bailey.

Table of Contents:

Tags and Accessibility

  1. Opening the Tags Palette
  2. Checking for Tags
  3. Checking for Reflow
  4. Creating a Text (Screen Reader) Version

Editing and Cleaning Up Tags

  1. Adding Tags Automatically
  2. Adding Manual Tags
  3. Adding Alternative Text
  4. Adding Table Headers
  5. Re-ordering Tags
  6. Deleting Tags

Tags and Accessibility

PDF accessibility depends on the existence of "Tags." Tags are essentially duplicate copy of your document content with descriptive code (tags) identifying each element of content. The codes are similar, though not exactly the same as, HTML tags and include such familiar elements as paragraphs, headers, forms, captions, lists, tables and table cells, and images/graphics. Acrobat tags also include many non-HTML elements, such as formulas, annotations, notes, parts, references, and sections.
Dual display in Acrobat of tagged pane and display pane.

When you create an "accessible" version of your PDF, you are essentially creating two copies of your content the one that is visually displayed in the standard view and the tagged version, which can only be seen by opening and reviewing the Tags Palette. Screen readers can only read the "Tagged" version of your document.

cautionIt is important to understand that after the document is converted to PDF and tags are added, the tagged version and the display version have no connection to each other. This means that you can delete content from the display version and that content will still be in the tagged version and vice versa. And, if you add content in the TAGS Palette, you also need to add that content to the display version (and, of course, vice versa).

Opening the Tags Palette

The WAC suggests you "dock" your Tags Palette onto your Acrobat workspace, so you can easily open and close the palette when you need to. To open your palette using the menus, go to VIEW then NAVIGATION TAGS then TABS. Once you dock the palette, you can examine the tags in a window next to your document (pictured above). Set your tag options to "Highlight Content" (pictured below) to automatically see which content is associated with which tag.
Tag palette display options set to "Highlight Content"

Table of Contents

Checking for Tags

Acrobat Professional includes two levels of automated accessibility checking: Quick Check and Full Check.

Accessibility Quick Check

The "Quick Check," only checks to see if any tags exist in the document. You can do a manual check equivalent to the "Quick Check" by opening the Tags Palette and looking for any tags.

Accessibility Full Check

The "Full Check," attempts to validate the existing tags and insure that all content is associated with a tag and that tags include all required information.

  1. From the ADVANCED menu, choose ACCESSIBILITY, then "Full Check." The "Full Check" dialog box appears.
  2. In the "Full Check" dialog box, set the following options:
    • Select "Create Accessibility Report" and "Browse" to set the location where your report will be saved.
    • Select "Include repair hints in Accessibility Report.
    • Select "Create comments in document." This will allow you to move through the problem spots using your Comments window.
    • Under "Checking Options," be sure to DESELECT the option to check for "Text language is specified." If you leave this box checked, Acrobat will put an error message for every line of text that does not have a specified language.
    Accessibility Full Check dialog box
    Pictured above: example of Accessibility Full Check dialog box with recommended options selected.

Repairing Errors Found in "Full Check."

After the "Full Check" is completed, Acrobat displays the number of each type of error found. If you set your check to "Create comments in document," you can now easily find and repair errors in your document using the Comment pane.

  1. From the VIEW menu, choose NAVIGATION TABS and COMMENTS. The Comments pane appears at the bottom of your document.
  2. Click on a comment with an accessibility error and the corresponding content will be highlighted in the document.
    Screen shot: 1. click on the comment created by the Accessibility Checker . . . 2. And the corresponding content is highlighed in the display.
  1. Click on the corresponding tag in the Tags palette and edit or, if necessary, add a manual tag to incorporate the missing content.

Table of Contents

Checking for Reflow

Beyond the presence and consistency of tags, you should check your document for read-order and "reflow." Reflow is the ability to reformat a document when text size is increased to avoid horizontal as well as vertical scrolling. Only tagged documents can reflow and reflow reflects the order of the tags.

To test for reflow:

  1. Open your document and increase the text size to 300% or more. You can increase the text size in a number of ways:
    • Press CNTRL + M and enter the magnification percent;
    • Press CNTRL and the plus sign (+);
    • from the VIEW menu, choose "Zoom to:";
    • type in the percent in the ZOOM toolbar: zoom toolbar showing 400%
  2. Turn on REFLOW by pressing CNTRL + 4 or from the VIEW menu, select REFLOW.

If reflow is available, the document will be reformatted to fit into the available screen area. In the table below are two examples of the same document zoomed to 400% magnification. On the left, reflow is not available and text bleeds off to the right of the screen. On the right, reflow is available (tagged PDF) and the content is reformatted to fit in the screen.

Document has no reflow.
No Reflow
Document with reflow.
Reflow

Table of Contents

Creating a Text (Screen Reader) Version

You can check your document for screen-reader compatibility in a number of ways, including using screen reader software to read your document and using Acrobat's "Read Out Loud" feature (on the VIEW menu). However, listening to your document in it's entirety may take a long time and may be difficult if you are not familiar with using assistive technology.

Another quick method to review the "screen reader version" of your document is to save the document in Acrobats "Text Accessible" format.

  1. From the FILE menu, choose "Save As."
  2. In the "Save As" dialog box, change "Save as type:" to "Text(Accessible) (*.txt)"
  3. Be sure to save the file in a location you can find again and click SAVE.
  4. From the FILE menu, select "Open"
  5. In the "Open" dialog box, change "Files of type:" to "All Files (*.*)."
  6. Navigate to your accessible text file and open it in Acrobat.
  7. Review your text version for missing content (alternative text for images?) and incorrect read-order (floating text boxes? Graphs and charts?).

The Text(Accessible) version includes alternate descriptions stored in image tags and presents the content in the read-order defined by the tags. It is essentially the same content presented in the same order that screen reader users would encounter your document.

Table of Contents

Editing and Cleaning Up Tags

Because the use of tags can be confusing and difficult to manage, in most cases, we discourage users from manually editing within the tags palette. However, in some situations, editing the tags is the only way to make a fully accessible document. In this section, we'll review some of the ways to add, delete, change, and reorder tags.

Adding Tags Automatically

If you do a "Quick Check" or if you manually review the Tags Palette and determine that there are no tags in your document, you can automate adding tags in two ways:

Best Method: Return to original version in Word (or convert PDF to a Word document using one of the many available converters) and reconvert to PDF using the Adobe PDFMaker Plug-in [see Converting Your Document to PDF above].

"No other option" Method: Use Adobe's tool. If you cannot recover the document into Word or another Office program that can add tags, you can use Adobe's automated tag feature.

  1. From the ADVANCED menu, choose ACCESSIBLITY, then "Add tags to document."
    Adobe will attempt to generate comprehensive tags. However, some elements cannot be properly tagged, such as:
    • Images no alternate text will be added.
    • Tables no header cells will be identified.
    • Floating objects (text boxes and graphs) may be ignored or placed incorrectly in the read order.
  2. Perform an Accessibility "Full Check" to identify tag errors.
  3. Manually review tags and add or change content as needed.

Adding Manual Tags

In some cases, you may need to add missing tags to only certain content (such as a text box or graph). The easiest method to add tags manually:

  1. Be sure your Tags palette is open and tags are visible.
  2. For text, use the "Select Text" option, highlight the content that needs to be tagged in your document. For other elements, use the Advanced Editing toolbar to select objects or text areas.
    screen shot: advanced editing toolbar
  3. In the Tags palette, from the Options menu, select "Create Tag from Selection."
  4. In the "New Tag" dialog box, select the type of content from the drop-down menu. You can add a Title, if you want this is for your use only and does not affect the document output. Titles can be helpful if you are working with a group of tags and need to be able to distinguish between them.
    example of new tag dialog box
  5. Your new tag will automatically be added to the END of the document tags. You must move it to the appropriate location within the document.

Adding Alternative Text

If an image or graphic does not have alternative text, you must add this by editing the properties of the associated tag. You may first need to add a "Figure" tag, as described above. Once the tag is in your document, add the alternative text by:

  1. Find the tag you wish to edit in the Tags palette.
    • To find a specific tag, select the content in the document. In the tags palette, under OPTIONS, select "Find tag from selection."
    • HINT: use the asterisk (*) or the slash (/) on the number key pad to open and close all tags and sublevels. Use the plus sign (+) to open one level of tags
  2. Right-click on the <FIGURE> tag of the associated image and choose "Properties."
  3. Enter a description of the image in the "Alternate Text" box in the TouchUP Properties dialog box (pictured below).
    TouchUp Properties Dialog Box
  4. Click CLOSE to accept your changes.

Adding Table Headers

Although Acrobat successfully converts tables created with the Draw Table or Insert Table options, table header rows and columns are never automatically defined in the converted PDF.
Thus, you must change these tags from table data cells (<TD>) to table header cells (<TH>).
Simple table with tags showing only table data, no table headers defined.
Text pictured above reads: In this simple example, tags at the left show only data cells (<TD>) even though the first row should include header cells (<TH>).

  1. Select the first header cell and find the associated <TD> tag in the Tags palette.
  2. Right-click on the tag and select "Properties."
  3. In the TouchUp Properties dialog box, change the "Type:" to "Table Header Cell."
  4. Click CLOSE to accept your changes. In the Tags palette, the tag should now appear as <TH>.
    screen shot showing table header cell and associated <TH> tag.
  5. Repeat for each header cell.

Re-ordering Tags

Tag order equals read order. Sometimes, Acrobat gets it wrong, especially around text boxes, graphics, and other special elements. Also, when you add tags without specifying a location, your tags will be added to the end of the tags list, meaning it will be read as the last content in the document.

Re-ordering tags can be a tricky exercise. There are two types of tag re-ordering: making a tag a sublevel and putting a tag after another tag and the difference is denoted by a small red arrow in the tags palette.

To move a tag beneath another tag:

  1. "Grab" the tag by clicking and holding your mouse on the red "tag" screen shot of tag. NOTE: do not put your cursor on the words or description associated with the tag or you will open the edit box, and not be able to move the tag.
  2. "Drag" the tag to the tag you want it to move beneath (that is, the tag above where you want the tag to move to). Look for the small red arrow that appears to indicate the tag will move "below" not "under" the tag:
    Showing arrow that indicates tag will be moved beneath the chosen tag.
  3. Release the mouse and the tag will now move beneath the selected tag:
    Tag <smallertxt> is placed below tag <Heading 3>

To make a tag a subset of another tag (nesting tags):

Subsets are used to group tags into like elements. For instance, the table data cell (<TD>) should appear as a subset of a table row (<TR>), which, in turn, should be a subset of a table (<TABLE>). Lists (<L>) should have at least one list item (<LI>) subset. When table cells or list items appear outside of their associated group, you may need to re-order the tags to create new subsets.

  1. "Grab" the tag by clicking and holding your mouse on the red "tag"screen shot of tag. NOTE: do not put your cursor on the words or description associated with the tag or you will open the edit box, and not be able to move the tag.
  2. "Drag" the tag to the tag that represents the top-level of the subset you want to create. For instance, if you want to put a new table data cell inside an existing row, you would drag the appropriate <TD> tag to the desired <TR> tag.
  3. Make sure the small, BENT red arrow appears (not the straight arrow as show above) indicating a subset will be created (tags will nest).
    Shows arrow that indicates tag will become a subset of the current tag (nested).
  4. Release the mouse and the tag will now become nested underneath the selected tag:
    Tag <smallertxt> is nested below the <Heading 3> tag.

Deleting Tags

You can delete any tags by clicking on the red taggraphic: tag icon and pressing the DELETE key. Remember: when you delete a tag you also delete any associated content for assistive technology users.

OSU Web Accessibility Center (WAC)
1760 Neil Ave 150 Pomerene Hall Columbus, Ohio 43210
Phone: (614) 292-1760 Fax: (614) 292-4190 E-mail: webaccess@osu.edu
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