Course Accessibility Checklist: Alternative Text

WHY USE ALT TEXT? 

Computers and screen readers cannot analyze images to determine what they represent, so for persons with visual impairments or certain cognitive disabilities reader, alternative (alt) text must be provided to convey the content and function of the images in all online content. When the content of an image, chart, graph, pictogram is used to present technical or detailed information, the alt text should include all the relevant data or the person using a screen reader will not have access to the content. 

ABOUT ALTERNATIVE TEXT

• Alternative text should be meaningful and replace (not describe) the images, charts, graphs, or diagrams.
• The length of alternative text may be limited by the application (Word, Blackboard) so it should be concise.
• You should describe the important information in an image. You do not need to describe every physical detail.

TIPS FOR WRITING GOOD ALTERNATIVE TEXT

• Try to answer the question "what information is the image conveying?"
• Begin your alt text by describing what type of image it is, such as, "Photo of," "Illustration of," or "Graph of."
• If the image does not convey any useful information, the alt text should just state what is in the image, for example "Photo of the Washington Monument."
• Alternative text should be fairly short, usually a sentence or less and rarely more than two sentences.
• If the image contains meaningful text, ensure all of the text is replicated because a screen reader will not read  text that is part of an image.
• If more description is required (e.g., for a chart or graph), provide a short description in the alternative text (e.g., a summary of the trend) and more detail in the long description.
• Test by having others review the document with the images replaced by the alternative text.
• For more complex images, charts, graphs, or diagrams include a long description. More information can be found at Writing Long Descriptions.

ALT TEXT VS. CAPTIONS

• If you want to add information to the page that would benefit both sighted users and users dependent on screen readers, this information should be in a caption. Remember that some sighted students need additional text to interpret a chart, graph, or diagram so captions are very helpful.
• Captions shouldn't duplicate the alt text. The alt text and caption should supplement each other, with the alt text written for screen readers and the captions written for all visitors.
• Alt text should never duplicate information that is elsewhere in the content of the page or in the image's caption.

These videos and websites will provide additional instruction on adding alt text in Word, PowerPoint and Blackboard.  

GRCCtv. Alt Text in MS Word. YouTube. 7 Aug. 2013. Web. 12 Oct. 2015.

Complex images such as charts, graphs, diagrams, and maps need long descriptions to ensure that the visually impaired student has access to all the information provided in the image.  The long description serves as a replacement for the image so it must be more that just a description of the image.  

Because various screen readers react differently based on the type of document (word, Blackboard content, PowerPoint, etc.) a safe practice is to include long descriptions of complex images in the actual document.  This ensures that the visually impaired person can access the information, and it provides support for all viewers of the document. Some sighted persons have problems interpreting complicated graphics so including the long description in the text benefits everyone.   

When you include a long description of an image in the text you will still need to enter some alt text.   You could actually use something like "Information about the image is included in the text under the image."  The screen reader will  alert the blind person that there is an image and let them know where the description of the image is.