Enhancing PDF Accessibility: Implementing Alternate Text

Video Overview:

In the rapidly evolving digital era, the need for accessibility in all forms of content, including PDFs, is increasingly crucial. To bridge the accessibility gap, setting alternate text within a PDF is a method that cannot be overlooked. This blog post provides a step-by-step guide to this process.

First Step: Tagging Images as Figure Tag

The initial approach to set alternate text involves ensuring that all the images in your PDF are tagged as a figure tag. Once they are tagged, simply navigate to the tags panel, right-click the figure tag, and select the properties button. This action opens up a section where you can input a description in the “alternate text for images” field.

Quick and Efficient Methods: Using the Accessibility Button

A faster way to set alternate text for multiple images simultaneously is by utilizing the ‘accessibility’ button. Clicking this option reveals an ‘Set alternate text’ command. Once activated, the system automatically detects all figures in the document and displays them alongside an associated text box.

This method streamlines the alternate text setting process and is particularly handy for documents containing numerous images.

The alternate text can be anything from a simple description of the image, like “a forest with Giant Sequoias” or “two robotic hands reaching towards each other,” to more complex annotations depending on the image’s content and context.

It’s vital to remember that images containing text should include the exact text as part of the alternate text, enhancing accessibility for visually impaired users who may rely on screen readers to access the document’s content.

Document Remediation: A Viable Alternate Option

Though learning to set alternate text within a PDF could be a valuable skill, you might prefer to invest your time elsewhere. For those who want to increase their PDF’s accessibility but don’t have the time or inclination to do it themselves, document remediation services are available.

These services take over the task of making a PDF accessible, freeing up your time for other endeavors. However, if you’re inclined to get your hands dirty and prefer doing it yourself, follow the steps outlined in this blog post or explore other resources for a more comprehensive learning experience.

Alternate text in Microsoft Word

Alternative text descriptions of images (Alt text) helps users understand the picture’s significance (or lack of.)

This content is typically only accessed with assistive technology. In some cases, if you hover your mouse over an image, it will provide the alternate text as a pop up.

Provide descriptions around the image in the source document for optimal results but remember that not everyone might be able to access the alternate text.

Video overview of how to apply alternate text to images in Microsoft Word

Image context

The context is everything for images in your document. If the image adds important information to the learning experience, it should be described. If an image does not add any value, you may consider marking it as decorative. Lets review some samples:

Sample 1 image

This image was found on the website which is trying to attract visitors. It needs detailed alternate text.

A forest with giant sequoias, the largest trees in the world, is a feast for the senses. The giant sequoias’ red/orange bark is distinct among the grey and brown bark of other trees. And if you stand beneath one of these giants, you can gaze all the way up its tall trunk and through its high branches to see sky above. The treetop is often hidden above the highest branches. If you are quiet and listen, you may hear a breeze rustling the foliage of smaller trees – the sugar pines, white and red firs, or incense-cedar. Or perhaps you’ll hear a woodpecker calling and tapping against a tree, seeking insects. If you have time to take a walk, you may see a giant sequoia along the trail – try to press your fingers against its spongy, thick bark.

Sample 1 image description

A forest with giant sequoias, the largest trees in the world, is a feast for the senses. The giant sequoias’ red/orange bark is distinct among the grey and brown bark of other trees. And if you stand beneath one of these giants, you can gaze all the way up its tall trunk and through its high branches to see sky above. The treetop is often hidden above the highest branches. If you are quiet and listen, you may hear a breeze rustling the foliage of smaller trees – the sugar pines, white and red firs, or incense-cedar. Or perhaps you’ll hear a woodpecker calling and tapping against a tree, seeking insects. If you have time to take a walk, you may see a giant sequoia along the trail – try to press your fingers against its spongy, thick bark.

Sample 2 Icon

This image is an icon and in my opinion does not offer any additional value to the content provided, so I would mark it as decorative.

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Giant sequoias grow at middle elevations along the west slope of the Sierra Nevada. While not the world’s oldest trees, they are known to reach ages of up to 3,400 years. Tree ring studies of giant sequoias provide a long record of climate and fire history, helping park managers and scientists better understand relationships of climate, fire, and the giant sequoia life cycle.

Sample 3 Pie Chart

This pie chart provides important information to the user. Because it is an image containing text, we need to provide all of the data in the description of the image.

Non-Wilderness. 340 Units. 14+ million Acres

Eligible. 21 Units. 17+ mill Acres

Proposed. 14 Units. 3+ million acres

Recommended. 17 Units. 5+ million acres

Designated. 50 Units. 44+ million acres

Sample 3 Alternate text

The National Park Service Wilderness by category is as follows:

  • Non-Wilderness. 340 Units. 14+ million Acres
  • Eligible. 21 Units. 17+ mill Acres
  • Proposed. 14 Units. 3+ million acres
  • Recommended. 17 Units. 5+ million acres
  • Designated. 50 Units. 44+ million acres

Additional things to consider when writing alternate text

  • Context is everything
  • Decorative images should be marked as decorative
  • Pie charts and other graphs will need all data described
  • Focus on the emphasis of the image
  • Avoid using “image of” in description
  • Be sure to check that the image does not just have the file name in the alternate text area. For example: jordison.png might be the default value in the alt text area for an image – be sure to spot check all images to ensure that the file name did not get inserted.
  • Keep alternate text less than 100 characters. If there is more text needed – be sure to include it next to the image on the page.

Text overview of how to apply alternate text in Microsoft Word

  1. Right click the image
  2. Select Edit Alt text
  3. Enter a description or mark as decorative
Right click the image

Select Edit Alt text

Enter a description or mark as decorative

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How to apply alternate text to images in Canvas

Images in Canvas need accurate descriptions for students who rely on screen readers. Images that convey a lot of text should be avoided whenever possible, and descriptions should be presented to provide enough information within context of the topic. Keep in mind the context of the picture, which may change the scope of the needed description. 

Image Context

Image context will change based on the audience and what you want them to learn about the image. The same image could have different descriptions depending on its intent. If you are creating the course or the content, remember that you are the artist and you get to pick the alternate text.

For more guidance on using alt tags, please see the Diagram Center’s Poet Training Tool

Diagrams and Charts

Alternate text for diagrams and charts can be accomplished but its possible these items might be better represented in a list or a table structure. Complex graphs and charts can include an over load of information.

Diagram and Chart Example

Convert diagrams and charts to tables

Adapted from DiagramCenter

Bonus Video on accessible bar charts

Guidelines:

  • Bar graphs should be converted into accessible tables.
  • Briefly describe the graph and give a summary if one is immediately apparent.
  • Provide the title and axis labels.
  • It is not necessary to describe the visual attributes of the bars, e.g. dark blue, light blue, unless there is an explicit need such as an exam question referring to the colors.

Description:

Figure 1 is a bar graph that measures percentage of vaccination coverage in five states over one year, from Q3 2006 to Q2 2007. In each state, the coverage increases over time. The data are summarized in the following table. All data are approximate.

First dose rotavirus vaccination coverage among children aged 3 months, by quarter – immunization information system (IIS) sentinel sites, United States, 2006-2007.

 ArizonaDistrict of ColumbiaMichiganMinnesotaMontanaOregon
Q3 200635%10%5%0%15%20%
Q4 200645%30%33%25%27%27%
Q1 200750%45%42%35%37%45%
Q2 200765%48%50%41%40%44%

Things to consider with alternate text and images in Canvas

  • Avoid “picture of” or “image of”
  • Avoid having the file name as the alt text – this will sometimes not show up in the accessibility check
  • Imagine explaining the picture over the phone to someone and use that as the alternate text.

Video Overview of how to apply alternate text to an image in Canvas

Instructional Guide – How to apply alternate text to images in Canvas

Step 1: Ensure you are in edit mode

Step 1: Ensure you are in edit mode


Step 2: Select the image you would like to add alternate text too and select Image options

Step 2: Select the image you would like to add alternate text too and select Image options

Step 3: Add appropriate alternate text or mark as decorative

Step 3: Add appropriate alternate text or mark as decorative
Canvas LMS
How do I make my Canvas page accessible?

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Alternate Text and Decorative Images in PowerPoint

What exactly is alternate text?

Images need accurate descriptions for students who rely on screen readers. Avoid using text-heavy photos and the description should provide enough information within the context of the topic. Keep in mind the context of the picture, which may change the scope of the needed explanation.

Images should never start with a “picture of” or “image of” as the screen reader will identify it as an image. The one exception to this rule is if the context of that information actually matters.

Is this a photography course? Is this an art course? If so, then it might be ok to use “image of” in the description.

How to apply alternate text to an image in PowerPoint Video Overview

Image Context

Image context will change based on the audience and what you want them to learn about the image. The same image could have different descriptions depending on its intent.

Special Notes

Be sure to check all images as sometimes the file name is inserted as the alternate text area. For example, jordison.png might be the default value in the alt text area for an image – be sure to spot-check all images to ensure that the file name did not get inserted.

Keep alternate text less than 100 – 150 characters. If there is more text needed – be sure to include it next to the image on the page. You can also link to a longer description using a separate document!

Want to know more about accessible pie charts and bar graphs?

When do I mark an image decorative?

When images are used that do not convey any meaning and are just for visual effect, it is possible to mark these elements as decorative with the latest versions of PowerPoint. After selecting the image and opening the Alt Text panel, select the checkbox “Mark as decorative”. This has the effect of making the image “invisible” to assistive technologies.

If an image does not include any alternate text information and is not marked as decorative, then assistive technologies may try to read out a file name or will announce the presence of a graphic, but with no additional information. This has the effect of informing the student there might be content, but the student does not have access to that information.

If sufficient information is described through text and images are used, consider marking the graphics as decorative to improve screen reader readability. 

Text Overview of how to apply alternate text to images in PowerPoint?

  1. Right click the image
  2. Select Edit Alt text
Right click the image
Select Edit Alt text.
alternate text in powerpoint

Then, enter a description.

  1. Enter an engaging alternate text description
  2. OR – Mark as decorative
Enter an engaging alternate text description
OR - Mark as decorative
alternate text in powerpoint
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