iPad showing HEART UK elearning course.

Accessibility for digital learning (4/4)

Part 4: Top tips for writing alt text

Welcome to our four part guide on accessibility for digital learning. In this fourth and final blog we will explore five key points you need to consider when writing alt text to make your elearning accessible for everyone, including those with learning, visual, physical and auditory difficulties.

Alternative text, otherwise known as ‘alt text’, is used to describe the appearance of an image on a page. This is applied so that screen readers can read aloud to visually impaired users throughout a course to describe what images are showing.

Alt text enhances accessibility across a variety of platforms, including social media – it also helps to improve SEO.

1. Describing the image

When writing alt text, you should think about:

  • What is the purpose of using the image?
  • What information does the image convey?
  • Is the image relevant to the content it is sat alongside?

Remember, when describing what the image is showing, it’s not necessary to mention colours or shapes unless they have meaning to the content.

2. Length

Excessive detail is not needed – keep it to the point!

Alt text shouldn’t be more than 150 characters and should only pick out the key features of the image that relates to the content it’s placed with.

3. Grammar

Always write alt text in sentence case and include punctuation marks to indicate to a screen reader when to take a pause before moving on to the next section.

4. Charts

There is no need to say ‘this is an image of’. A screen reader will always announce to the user when there is an image before reading out the description.

The exception to this rule is for the description of a chart. Unless you mention in the description that it is a bar or pie chart and what it is showing, the user will not know what is being described to them.

If there is a particular source you have taken the chart from, you can always link to the site where the information of the chart is explained.

5. Where alt text is not needed

All images require some form of alt text.

If an image is purely decorative and is not adding anything to the content, you do not need to add a description. Instead, input one of the following:

  • “”
  • alt=””

Using either of these options will indicate to a screen reader that this image can be skipped.

If no text is written in the alt text, a screen reader will read out the name of the image file which may confuse the user.

What’s next?

You have now reached the end of our guide on how to make your digital learning fully accessible.

Refer back to any of our previous blogs in the series to further support your learning.

Part 1: Top tips for writing content

Part 2: Top tips for writing link text

Part 3: Top tips for design

Part 4: Top tips for writing alt text