For Faculty

Got Images? Get Alt Text

by Jackie Luft, Ed.D

The last few months we have been focusing on the importance of creating an accessible syllabus and the seven steps to that process. This month, we will go over alternative text. By creating alternative text for your images, a person using a screen reader will be able to access the same information as a normal sighted user.

Many documents and even syllabi include non-textual elements. These include  graphics, photos, images, smart art, charts, graphs, clip art, and others. How can a non-sighted user be able to obtain the information these non-textual elements provide in the document? This is where the creator of the document must explain the element, which is called alternative text. You will also see this referred to as “alt text” or “alt tags”. Simply put, the non-textual element will need to be described in text as to the content of the element. For example, often an instructor will include an image of the textbook along with the ISBN number, name of text and author. This is very helpful for students when they go to purchase the book, so they can see what the textbook looks like. A non-visual person would not be able to see the image but if there is alt text describing the image, then the student will be able to understand what the book looks like.

Sometimes instructors include non-textual elements in the form of decoration. Having a visually appealing document does not have to be sacrificed in order to have an accessible document. If you do have an image that merely for decoration, you simply need to add “ ” (quotation marks) in the alt text description. The screen reader will read this non-textual element as “image-null” or simply skip over the image. The user of the screen reader will know that image is not necessary for comprehension of the document. If the the image is not identified as just decorative, the screen reader will state, “Image”. This will leave the user with the suggestion that there is an image that contains information that is not being conveyed to them.

Alt text should not be very long. The typical suggested guide is about the size of a tweet, 140 characters. Some screen readers read more than others but the length of a tweet is a good guide. You also don't have to describe every single small detail; you just need to state why the image is important to the text. An image of a small flower would have a different alt text for a children's text then a graduate level biology course.

What about non-textual elements that convey a lot of meaning? For example, a detailed graph or chart. Obviously you would not be able to include all the information in 140 characters or less. In these instances, we would use a long description. You can either write the context of the image in the text near the non-textual element or create an appendix or separate document of long descriptions. In journal articles that include complex charts and graphs, you will see the context explained in the text: it often reads, “In figure 4.3...” or something similar. Whichever method you choose in the alt text description box, simple state, “Long Description in Appendix A” or wherever you have written the long explanation of the element.

Let us know at the Online Accessibility Lab if you have any questions!