Why Add Alternative Text Descriptions?
Alternative text is added to an image to provide a textual alternative to visual information. It is important to remember that some users won’t see your information, they’ll hear it!
According to the principles of Universal Design for Learning, images should be understandable in multiple ways. By adding an alternative text description to an image, you make its meaning available to people who, for whatever reason, cannot see it. Whether due to technological limitations or visual impairment, many people require a text alternative to visual information.
How to Add Alternative Text to an Image (Office 2007)
(The following instructions apply to Word documents saved in the Word 2007 or .docx file format.)
To add an alternative text description to an image, follow these steps:
- Place the image in focus by either clicking on it or using the keyboard.
- Pull up the context menu by pressing the Context Key, or by right clicking on the image.
- Choose "Size..." from the context menu (Figure 1).
- Choose the "Alt Text" tab in the Size dialog (Figure 2-a), and enter your alternative text description of the image (Figure 2-b).
Figure 1: Accessing Alternative Text through the Size Dialog
To add alternative text to an image, right-click on the image and choose Size...
Figure 2: Adding Alternative Text
Select the “Alt Text” tab, and enter a meaningful description of the image.
How to Add Alternative Text to an Image (Word 2003)
The following instructions apply to Word 2003 documents, as well as Word 2007 documents saved in the "Word 97-2003 Document" or .doc file format (also called Compatibility Mode).
To add an alternative text description to an image, follow these steps:
- Choose View > Normal (Ctrl+Alt+N).
- Select the image.
- Right-click (Shift-F10) and choose Format Picture.
- Select the “Web” tab (Figure 3-a).
- Enter an alternative text description of the image (Figure 3-b).
Figure 3: Adding Alternative Text
To add alternative text to an images, right-click on the object, choose Format > Picture, click on the “Web” tab, and enter a text description.
How to Describe an Image
Alternative text should describe the meaning of an image rather than its appearance. For example, instead of “Sign hanging on laboratory door,” tell the viewer what the image signifies: “Each laboratory has safety policies posted on the door.”
Keep descriptions as short as possible. It is generally unnecessary to begin a description with “photo of” or “picture of.” If describing a chart or graph, be as complete as possible.
In addition to alternative text, captions may be used to convey visual information to all users. Images can also be described in the text of your document.
A Meaningful Image or Just “Eye Candy”?
If an image contains important information, it should be given a meaningful alternative text description. On the other hand, if the image is merely decorative, a description is a waste of time—for both the author and reader. Such images are routinely skipped over by readers who can see them, and users of assistive technologies will want to do the same.
Unfortunately, Microsoft Office offers no means of indicating that an image should be ignored. The situation is easier in for HTML and PDF. In HTML, you simply add a “null” or “empty” alternative text attribute to the <img> tag. For example, <img alt="">. In a PDF document, you tag the image as an “artifact.”
For more information about alternative text in HTML and Adobe PDF, see the following:
References
- Accessible Digital Media: Design Guidelines for Electronic Publications, Multimedia and the Web
- The definitive guide from the National Center for Accessible Media (NCAM) offers everything you wanted to know and more.
- How to Create Descriptive Text for Graphs, Charts & other Diagrams
- A Descriptive Text Tutorial Web Accessibility Tutorial for Creating Descriptive Text for Diagrams, Charts & Other Graphics from the Center on Education and Work from the University of Wisconsin-Madison.
- Research-Based Guidelines on Web Design and Usability Issues
- Guidelines published by the U.S. Department of Health and Human Services. Includes a clear discussion of alternative text.
- Text Alternatives for Images (alt-text)
- One section of a 10-section tutorial by Jim Thatcher on web accessibility that clearly explains many image labeling issues.
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