Text alternatives are required for all images (except decorations), infographics and audio/video playback. Text alternatives, or “alt text” provide users who use screen readers descriptions of visual content and ensures your message is clearly communicated to all users.
We’ll look at how text alternatives can be used in the following use-cases.
Images on a web page
- Keep the “alt text” simple and objective.
- Describe the image to the user in conversational language
- Descriptors of subject characteristics, such as gender or race, should be avoided unless relevant.
- Technical or promotional language should be avoided.
- Example (image above): “A researcher uses optometry equipment to examine a patient”
- Keep the “alt text” to fewer than 125 characters.
- Many screen-reading tools will stop reading past this point.
- Don’t start “alt text” with “Picture of...” or “Photo of...”.
- Describe only the image. Screen reading tools (and search engines) will identify it as an image from the web page’s HTML source code.
- In some cases, it may be necessary to include details such as “archival photo of” or “architects rendering of” for context.
- Use visible caption text in addition to “alt text”
- Alt text is rarely visible on screen. Captions always are.
- Captions can help all users to better understand the image and place it in appropriate context.
Infographic descriptions
Infographics can be very effective tools to communicate complex or procedural information, however they cannot be read by most assistive devices. If used, be sure to include a longer-form version of the information. Depending on the information, tabular data may be useful. You may also choose to provide the information through on-page copy.
Captions
Video and audio recordings are increasingly being used across the University website and the broader internet. These mediums can increase the impact of our messaging and allow us to create vivid, high-quality user experiences.
However, not all users are able to see or hear videos or audio content. It is important to provide these in alternative formats as well. Many popular video hosting platforms, such as YouTube provide auto-transcription services. These can help get you started, but it is important that you take the time to review the transcript and correct any errors. Transcripts can be posted to the website as text on a webpage or accessible downloads.