Provide alternate text for important graphics.
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Applicable user interfaces
This checkpoint only applies to Lotus Notes applications viewed through the Notes client.
Note: Applications that support both the Notes client interface and the Web interface must complete both the Web checklist and the Lotus Notes checklist. When completing the Web checklist, related techniques and examples for Domino developers are found in Web checkpoint 1.1a – Text alternatives.
Adding text descriptions to graphics allows users who are blind to visualize the graphics. Screen readers use the text description (alternate text) to identify the graphics to the user.
When graphics are not used as links, use alternate text carefully. A person having to listen to a document cannot ignore text the way a person viewing the document can ignore a graphic. If the graphic is not important or if it is redundant, assign null alternate text so that the assistive technology will ignore the image.
Required development techniques
The following techniques are the minimum required to meet Checkpoint 3.1 from the Lotus Notes Application Accessibility Checklist:
- Provide alternate text for all graphics and graphic links.
- Select the graphic and open the Picture Properties box.
- In the Alternate Text field, enter a brief description for the image. If the image is a picture of an object, the object's name would be appropriate alternate text. For example, the alternate text for a picture of a red balloon would be "red balloon".
- If the image is not a link and is redundant or unimportant, enter "" in the the Alternate Text field. This will assign null alternate text to the graphic so it will be ignored by assistive technology.
- Provide alternate text for applets to describe the applet's function.
- Open the Java Applet Properties box and select the Basics tab.
- In the Alternate Text field, enter a brief description of the applet's function.
- When using icons in views:
- If custom icons are added to views, assign a meaningful filename to the image used for the icon. You cannot assign alternate text to custom view icons, so assistive technology will read the filename for the image. The filename should describe the image. For example, an icon used to show a document is complete should have the filename complete.jpg.
- When Notes standard icons are added to views, no additional action is needed. Alternate text has already been defined for the standard icons.
- If the graphic is the only object on a page, alternate text should always be provided. When someone using a screen reader navigates to the page, the screen reader will be silent if alternate text has not been provided for the graphic. The user will not be able to determine if there is a problem or if page is blank.
In the example below, the Picture Properties box shows the alternate text for the graphic with the text "Done".
Recommended development techniques
The techniques above are required; the following technique is recommended to enhance accessibility:
- If the graphic is an image of text, the alternate text should match the text on the image. For example, if the image is the word Feedback, the alternate text should be "Feedback" and not "Click here to provide feedback".
- Keep alternate text short and to the point. There are times alt text needs to be more descriptive, such as with a complicated graph or chart. In their document, Techniques For Accessibility Evaluation And Repair Tools, the Evaluation and Repair Tools Working Group of the W3C Web Accessibility Initiative recommends a maximum of 150 characters for alternate text and a maximum of 60 characters for image links.
Required test techniques
Test the application to ensure that it complies with accessibility requirements.
Install the following tools to test this checkpoint:
View the Notes client application with a screen reader to verify images have appropriate alternative text.
©2009 IBM Corporation
Last updated August 25, 2009.