Making PowerPoint Slides Visually Accessible

PowerPoint has easy ways to check and add accessibility features. For example, Check Accessibility and Selection/Reading Order are the two primary tools for making PowerPoint slides accessible. You don’t need to discard your old slides. Instead, you can simply change or add some features.

Start with PowerPoint Accessibility Tools, then continue with these tips and detailed instructions to make PowerPoint slides accessible to blind and low-vision users:

Include alternative text on images

Alternative text (alt text) conveys the “why” of the image as it relates to the content of a document or webpage. It is read aloud to users by screen reader software, and it is indexed by search engines. It also displays on the page if the image fails to load, as in this example of a missing image.

See the Diagram Center’s guide on writing good image descriptions.

Missing alt text is a common barrier for PowerPoint users with visual impairment. Make sure you add alt text to any important graphics. When we checked accessibility earlier, you might have noticed that many images are missing alt text in the Check Accessibility panel. We will now show how to add alt text in different scenarios.

How to add alt text

1. In PowerPoint, right-click a picture and find View Alt Text.

the "View Alt Text" option highlighted context menu after right clicking a picture

2. Write and edit the alt text.

The Alt Text pane will show up on the right. Add a description that conveys the meaning of the image.

This is a screenshot of a PowerPoint slide and the Alt Text Panel. On the left, there is a PowerPoint slide with two pictures which both have some text descriptions below. on the right we see the "Alt Text" pane, which includes the alt text of one picture in one textarea. There is also description of alt text above the textarea. Below the textarea, is a button called "Mark as decorative" above a button "Generate alt text for me".

3. Make your alt text descriptive.

It is important to make your alt text descriptive and specific. For example, the alt text above “This is a profile picture of a classic 1980s man who is into rock music with long hair” detailed the picture pretty well. In contrast, you shouldn’t simply say “Customer X”.

See the Diagram Center’s guide on writing good image descriptions.

4. Avoid unnecessary long alt text.

Your alt text shouldn’t be unnecessarily long. Consider why you included that image. What point were you trying to get across? Use this purpose to help you select what details to include. Look at the example below. For the scatter plot and red line, we actually don’t care about the number of points or the color of these points or lines. We want to convey that the line is the singular vector that captures the most variance of these points, meaning that the line is aligned with the points in 2D space.

This is a screenshot of a PowerPoint slide and the Alt Text Panel. On the left, there is a PowerPoint slide with a scatterplot and a red line fitting a regression of the scatter plot. On the right, the alt text is "This graph is the same 2-D scatter plot and a regression line y=x. All the scatter points are surrounded by this line. Even though this is a s-d on a plot, the actual dimension can be captured by a line (the y=x regression line), which is 1-d.".

5. Include tactile graphics when possible.

Complement graphs with tactile graphics when possible. For the dimensionality reduction example, it may be beneficial to add tactile graphics so that the students can “feel” what you are talking about. See Create Tactile Graphics.

Use caution with automatic alt text generation

When adding alt text to images in PowerPoint, you might have noticed a Generate alt text for me button. While this feature can be convenient, we advise caution when using it. It’s essential to understand that this function, in its current form, does NOT always produce accurate or comprehensive alt text. Nevertheless, we will guide you on how to utilize this tool and subsequently review the auto-generated alt text for accuracy.

1. Click the Generate alt text for me button.

View Alt Text … → Go to the Alt Text panel → Generate alt text for me

2. Review the generated alt text.

Note that the quality of alt text is not guaranteed, so please do not just click that button and call it a day. If I generate the alt text automatically for the plot, it’ll just show a non-descriptive text, “Diagram”, which is not informative at all.

This is a screenshot of a powerpoint slide and the Alt Text Panel. On the left, there is a powerpoint slide with a scatterplot and a red line fitting a regression of the scatter plot. On the right, the auto-generated alt text is "Diagram, description automatically generated."

Language models and alt text generation

We recommend not using tools like GPT4 to generate alt-text. These models often produce very verbose text descriptions and may get numerical values incorrect. We highly recommend taking a very close look, and manually verifying the alt-text if a generative AI program is used to generate them.

Mark unimportant images as decorative

Decorative images are images that do not convey any information. Think of a background image that simply serves an aesthetic purpose. In this case, you can mark the image as decorative so that screen readers will skip it. Otherwise, the screenreader will focus on and read out the element, confusing the screenreader users. The mistake is especially problematic when the slides contain many of these elements.

In the example below (and for the purpose of this guide), the Pinterest logo doesn’t convey important information, so it should be marked as decorative.

To mark an image as decorative: View Alt Text … → Go to the Alt Text panel → Mark as decorative

This is a screenshot of a PowerPoint slide and the Alt Text Panel. On the left, there is a PowerPoint slide with a few pictures from Pinterest. On the right is the "Alt Text" pane. In the pane, the "Mark as decorative" is selected.

Remember footers!

In the example above, there’s also a template footer that specifies the date, instructor, course title, and URL. We advise to mark them as decorative on subsequent slides to prevent redundancy. This ensures that screen readers don’t repetitively read out the same information, thus saving the user’s time.

Group images on PowerPoint slides

For complex diagrams with many sub-images, if you don’t group the pictures, the screen reader users will likely (and unnecessarily) be overwhelmed and confused. This page includes two approaches to group images on PowerPoint.

Why group images?

Let’s walk through the example below about Singular Value Decomposition (SVD). As you can see it’s an SVD equation, A=UΣVT, but there are just so many unorganized pointers such as m rows, n columns, approximation sign (≈), r columns/rows, etc. You can see the messiness on the slide’s Selection Pane below. Note the reading order section; it is important!

This is a screenshot of a PowerPoint slide and the Selection Pane. On the left, there is a PowerPoint slide titled "Reducing Matrix Dimension", followed by text description, and then followed by math equation A \approx U \Sigma V^T. All three components are laid out in matrix format to make it easy to comprehend. The rows and columns numbers are denoted in various numbers. on the right is the "Selection Pane" pane. In the pane, 11 textboxes of the components from the left slide are selected.

There are two ways to resolve this issue…

Approach 1: Group the images on PowerPoint.

1. Select each of the images you want to group.

Right-click on the selected images/texts, etc → View Alt Text … → Mark as decorative. By marking them as decorative, the screen reader will streamline its focus onto the entire group rather than each individual element. We want the screen reader to read the grouped content as a cohesive unit. This prevents potential confusion or redundancies, leading to a smoother user experience.

This is a screenshot of a powerpoint slide and the Alt Text Panel. on the left, there is a powerpoint slide titled "Reducing Matrix Dimension", followed by text description, and then followed by math equation A \appro U \Sigma V^T. All three components are laid out in matrix format to make it easy to comprehend. The rows and columns number are denoted in various numbers. On the right is the "Alt Text" pane. In the pane, "Mark as decorative" is selected.

2. Group the components.

Right-click on the selected images/texts, etc → Group → Group. (Yes, “Group” under “Group”.)

3. Add alt text to the group.

At this step, all the components should be in a group. You need to add alt text to the group.

This is a screenshot of a powerpoint slide and the Alt Text Panel. On the left, there is the same powerpoint slide titled "Reducing Matrix Dimension". This time the math equation components (formerly 11) are grouped into one giant component. on the right is the "Alt Text". In the alt text text area it says "An equation of SVD (Singular Value Decomposition). The point is that we can approximate an original matrix by an equation of three smaller matrices. The original matrix A can be approximated by Matrix U multiply \Sigma matrix multiple the transpose of the V matrix."

Approach 2: Save as Picture

1. Select the components and save as picture.

Select the pictures you want to group → Save as Picture …

The same powerpoint slide as above, but all components are selected. Then right button is clicked. In the context menu, "Save as Picture" is selected.

2. Drag the saved picture from your folder to this slide.

If you want to revert the saved picture to its original position, don’t delete the original components. You can overlay the saved picture with the original components. When they overlap, cut the saved picture → select the original components → delete → paste the saved picture. You are all set now.

3. Add alt text to the picture.

You can add alt text to the new component as an image!

Make animation accessible

It is common to have animation on your slides, but screen reader users rely on the correct reading order and detailed alt text.

In the example below, the slide sequentially displays the formulas for “Jaccard Similarity Metric,” “Cosine Similarity Metric,” and “Pearson Correlation Coefficient.” With each animation, the corresponding examples (i.e., rz, ry) are revealed in green text on the right-hand side of the slide.

This is a screenshot of a powerpoint slide and the selection pane. On the left, there is a powerpoint slide with a few formulas about "Jaccard Similarity Metric", "Cosine Similarity Metric", and "Pearson Correlation Coefficient". Next to each formula are some explanation that would be animated to display. On the right, the selection pane displays the reading orders of these elements on the powerpoint slide

1. Check the reading order.

Make sure that the reading order follows the animation order: the first element in the reading order should be the first element animated. Below is the animation order in the Animation Pane.

This is a screenshot of the animation pane. On top it displays a green triangle followed by text "Play All". It is followed by an up and a down arrow and a delete button. Below this row shows "animations". Each animation is one row (it has 5 rows on the screenshot). Each animation has the animation order (0, 1, 2, ...) followed by the title of these animation. (Each animation can consist of multiple text chunks on a powerpoint).

2. Avoid adding animation inside of one single text box.

Don’t add animation inside of one single text box. For example, don’t lump all three similarity metrics into one giant text box and add animation inside. Instead, create three text boxes, each of which represents one metric. Having separate components makes it easier to adjust the reading order.

Add LaTex for math notations

Make sure to add LaTex for complex math notation if you just include a screenshot/picture of the math. Some students with visual impairments are able to read LaTex representations. Consider the example about TF-IDF below:

This is a screenshot of a powerpoint slide and the Alt Text Panel. On the left, there is a powerpoint slide with a few formulas about "Jaccard Similarity Metric", "Cosine Similarity Metric", and "Pearson Correlation Coefficient". Next to each formula are some explanation that would be animated to display. On the right, the selection pane displays the reading orders of these elements on the powerpoint slide

In the example, there are texts, inline math symbols (e.g., ƒij), math equation as one line (see image, right), arrows, and explanation. It involves many components and adding alt text to each single component can be challenging both for the authors and the readers.

Sample equation with inline math symbols.

To resolve this problem:

1. Keep your original slide (yes, regardless of how many components).

2. Mark all components decorative.

This is the same screenshot of the powerpoint and the alt text panel as above. This time, all the math components and the associated texts are marked decorative on the alt text panel.

3. Create another white box and add alt text as LaTeX to it.

This is the same screenshot of the powerpoint and the alt text panel as above. This time, a white box is highlighted and the alt text for this empty box is the math and text that we marked decorative previously.

LaTeXiT is a great tool to quickly iterate on the LaTeX formula as you work on your slides.

Represent flowcharts and graphs with Mermaid

Flowchart is a common chart in slides that represents a workflow or process. While you can certainly add detailed text description in your alt text, you can augment your flowchart with Mermaid markdown instead.

With Mermaid markdown you completely specify diagrams and visualizations using text. It is especially beneficial to augment flowcharts. BVI students can read or use the Mermaid declarative grammar found in the alt-text. What we are doing here is transforming graph structure in a declarative format so that screen readers can interact with them. Referring to the Mermaid documentation and the URL to an online playground, let’s look at an example:

This is a screenshot of a powerpoint slide which contains a flowchart with low color contrast (light blue, light yello, and light green)

We show an image from an original PowerPoint slide. First let’s change the color contrast:

This is a screenshot of a powerpoint slide which contains a flowchart with low color contrast (blue, black, and orange)

We will add the Mermaid diagram. You can also look at the image that Mermaid compiles A Mermaid-compiled flowchart.

This is a screenshot of the same flowchart in Mermaid

Create tactile graphics

Sometimes alt text might just not be enough, you can reach out to the UW Access Technology Center‘s Braille Embossing services (or the equivalent office at your university or college campus) to print out the tactile graphics of some visualizations. For example, the image below is important to understand clustering. We could rely on alt text, but the tactile experience will augment the experience for blind students.

This is screenshot of a cluster view of some dots. There are dots of 4 colors (red, blue, yellow, and green). Dots of the same color are clustered together. This would be communicated more effectively with a braille artifact.

Planning early is critical

It is expensive and time-consuming to print out tactile graphics, so it typically makes sense to select only images that are essential to understand foundational concepts. Note that in CSE547 we started one quarter in advance — still, not all tactile graphics could be delivered on time during the course the following quarter. This delay might be even longer at other universities.

To create the Braille artifacts:

  1. Have a folder of the images that you need to print out. Ideally, the image will be in svg format.
  2. Contact the appropriate office (the UW Access Technology Center‘s Braille Embossing services) indicating that you need help with tactile graphics. They can help facilitate this process.