Some tagged PDFs might not contain all the information necessary to make the document contents fully accessible. For example, to make a non-text document content available to a screen reader, the PDF should contain alternate text for figures and replacement (actual) text for some links, formulas and abbreviations.
There are several ways to add alternative text to images and figures:
- The “Set Alternative Text” command in the Accessibility tool
- The “Set Alternative Text” command in the Make Accessible Actions wizard
- The Touch Up Reading Order tool (refer to “Add Alternate Text with the Touch Up Reading Order Tool”).
- The alternative text field of the Object Properties dialog in the Tags panel
Note: Alternate/Actual text should be short and concise. The Alternative Text field should be used to set alternative text for figure elements. The Alternative Text field is not announced by screen readers for non-image element. The Actual Text field is announced instead when it is present on a text element.
Add Alternate Text to a Figure
To add alternative text to a figure using the Set Alternative Text command:
- Activate the “Set Alternative Text” command from the Accessibility tool pane or from the Make Accessible wizard.
- Enter short but descriptive alternative text for each image.
- Decorative images can be marked as decorative in this wizard, which will make the image an artifact.
Note: The “Set Alternative Text” command in the Accessibility tools will display the alternative text, if any, for all images. The same command in the Make Accessible Actions wizard will also allow the entry of alternative text for images that are missing alternative text.
To add alternative text to a figure using the Tags panel:
- Choose View > Show/Hide > Navigation Panels > Tags.
- Expand the logical structure tree to find and select the desired <Figure> tag element for the image.
- Choose Properties from the Options menu in the Tags panel.
- In the Object Properties dialog box, click the Tag panel.
- Type text in the alternative text field that describes the figure.
Add Actual/Alternate Text to Links
When a link contains a URL, screen reader will announce the URLs of web links. However, meaningful alternate text for links can be much more useful. Alternative text is also useful for links that have the same link text and or link text that is not descriptive when taken out of context. For example, a link with text of “http://www.whitehouse.gov” could be presented using an Actual Text property of “White House web site”.
Note: Actual text must be added only to tags that do not have child tags. Adding actual text to text links or alternate text to an image link’s parent tag prevents a screen reader from reading any of that tag’s child tags.
Add alternate/actual text to the <Link> tag of a link.
- In the Tag panel, select the <Link> (<Figure> for image link) tag for the link to add actual text to and choose Options > Properties.
- In the Object Properties dialog box, activate the Tag tab.
- Type the text in the “actual text” field for the text links, or type text in the “alerntaive text” field for image links.
- Activate the Close button.
Add Actual Text for an Abbreviated Term, Forumla, or Non-Unicode Symbol
It may be useful to provide expansion text for some abbreviations, particularly when assistive technologies may mispronounce an abbreviation, or where formulas or non-Unicode symbols are used.
In the Tags panel:
- Locate the term to provide actual text for by performing one of the following:
- Expand the tag tree as needed to see the elements that contain the abbreviation.
- Use the Touch Up Text tool or the Move to or Make Changes to Object tool to select the item in the document.
- Choose Find Tag From Selection from the Options menu to locate the text in the tag tree.
- If the abbreviation includes additional text, cut the additional text and place it in a new <Span> child tag within the same <Span> parent tag.
- Choose Properties from the Options menu of the Tag tab.
- Type the actual text for the item in the Actual Text field.
- Activate the Close button.