Web Accessibility: PDF Documents
PDF files have been a convenient way to deliver print documents online, but they remain a challenge to make accessible. Problems include:
- The difficulty and cost of making PDF files accessible (Penn State, n.d.):
- The full version of Adobe Acrobat is required to inspect and insert image alt text and other fixes into a PDF file.
- The process of repairing PDF files is both time consuming and can lead to inconsistent results. More training is required to make PDF content accessible compared to formats like Microsoft Word or PowerPoint.
- Using a PDF repair service like CommonLook or Braille Works is expensive.
- Very large PDF files can be slower to download than a webpage (Penn State, n.d.).
- PDFs are a proprietary format created by Adobe, so not everyone can open and read them without downloading additional software (Kalbag, 2017, p. 83).
- PDFs consisting of scanned pages are really a series of images, and as such are inaccessible to screen readers (Penn State, n.d.).
- PDF documents are usually formatted to be printed vertically, but computer monitors are generally horizontal. This mismatch causes users to scroll more often than on a website, which can be difficult for users with mobility impairments (Penn State, n.d.).
Because of these problems, many experts recommend avoiding or minimizing the use of PDF files as a sole source of online information (Penn State, n.d.).
There are instances when a PDF file can deliver material effectively (Penn State, n.d.):
- To post material that uses specialized characters, such as in science fields like chemistry and mathematics.
- To provide print manuals and print forms online. These would include blank forms, how-to instructions designed for print, contracts, or long user manuals.
In order to make content more accessible, consider these alternatives where applicable.
- Instead of using PDFs to provide content, recreate the content using a webpage. It will be easier to find, easier to read, and much more accessible (Kalbag, 2017, p. 83).
- If a PDF is used to create a graphic-heavy poster or flyer, ensure that the information is also available outside the poster or flyer (Penn State, n.d.), such as text on a webpage.
- If a PDF is used to post a report, consider posting the report in Microsoft Word instead (Penn State, n.d.).
- If a PDF is used to post a presentation, consider posting the report in Microsoft PowerPoint instead (Penn State, n.d.).
- Avoid converting text with multiple columns into a PDF file. A screen reader may unexpectedly read text across columns. It will also result in additional scrolling as each column is read, making the information harder to process for people with motion impairments and some cognitive disabilities (Penn State, n.d.).
If a PDF is required:
(Penn State, n.d.)
- Generate a “tagged” PDF from the document source whenever possible. The specific method of doing so will vary depending on the file format and operating system. Some options are:
- Notify users when a link goes to a PDF file. Example: User manual (PDF).
- If you can’t generate an accessible PDF, use a PDF repair service or the repair tools in Adobe Acrobat (see more below) to ensure accessibility.
Any tagged PDF file should be inspected to verify that the tagging structure is sound.
Fixing PDFs with Adobe Acrobat
Adobe Acrobat Pro (XI and DC versions) is the most commonly used program to evaluate, repair, and enhance the accessibility of existing PDF files (WebAIM, 2019). Remember to save often!
Set up Acrobat
The most important tools for making PDFs accessible are the Make Accessible Wizard and the Accessibility tools pane (WebAIM, 2019). They are hidden by default in Acrobat, so you will need to go through a one-time process to make these tools visible and available (WebAIM, 2019).
Accessibility Tools Pane & Action Wizard
For Acrobat Pro DC
- Click the Tools tab in the upper-left corner of the window.
- In the search bar below the tab, enter the word “accessibility”.
- When the Accessibility tools appear, click the Add
- Go back to the PDF you are working on and you will now see Accessibility in the right-hand sidebar. Click it to open a group of accessibility tools.
- To make the Action Wizard visible, repeat steps 1 – 3, except search for “action wizard”.
For Acrobat Pro DC
- Click the word Tools to open its sidebar.
- Open the Options menu ( ) in the upper-right corner of the Tools sidebar.
- Click on the Accessibility pulldown to expand its section.
Additional instructions are on WebAIM’s PDF Accessibility – Set up Acrobat webpage.
Make Accessible Wizard
The first step in making a PDF accessible is by using the Make Accessible Wizard. It’s a helpful way to ensure that you don’t miss any steps while making your document accessible (Purdue University Innovative Learning, 2018).
- If the Action Wizard is not visible, refer to the instructions in the previous section.
- In Acrobat Pro DC, select Tools and then click the Action Wizard button. An Actions List will appear. Select “Make Accessible”.
- In Acrobat Pro XI, select Tools and then click the Action Wizard panel. Select “Make Accessible”.
- Click the Start button. The wizard will take you through several steps.
- Description: focus on the Title Uncheck the “leave as is” checkbox and input a title that describes the content. For example: Biology Fall 2022 Program Progression Guides. Select the OK button.
- Recognize Text: Acrobat Pro will recognize the text if this is a scanned PDF. Whether or not it’s a scanned PDF, select the OK button.
- Fillable Form: if the document contains a form, select Yes, Detect Form Fields. If it doesn’t, select No, Skip This Step.
- Set Reading Language: select the language of the document and select the OK button.
- Image Detection: Acrobat Pro will detect all images that don’t have alternate text. Select the OK button to start the process.
- Set Alternate Text: Acrobat Pro highlights the image and gives you a text field to enter the image’s description. If the image is decorative, select the “Decorative figure” checkbox.
- If the PDF file has multiple images that need alt text, use the next and previous arrows (see image above) to add alt text to each image.
- When you are finished adding alt text to your images, click Save and Close.
- Accessibility Checker: Select the Start Checking When Acrobat Pro finishes checking the file, it opens the accessibility checker panel in the left sidebar. The panel identifies issues that need to be checked manually, such as color contrast.
Watch Purdue's video on how to use Adobe Acrobat's Make Accessible wizard.
Run Accessibility Full Check
After you have run the “Make Accessible” wizard, Acrobat Pro will run a full accessibility check on the PDF file. It will tell you where the accessibility issues are in your PDF and how to fix them. It can also be run independently of the Make Accessible wizard (Purdue University Innovative Learning, 2018).
Accessibility Full Check
- To run the report, go to View → Tools → Accessibility.
- In Acrobat Pro DC: the Accessibility sidebar will appear on the right. Select Make Accessible, and then Full Check (it’s at the bottom).
- In Acrobat Pro XI: select the Action Wizard panel & then Make Accessible. Then select Run Accessibility Full Check.
- The results in the “Accessibility Checker” panel lists common document elements. Elements with problems will be in bold, with the number of issues in parentheses.
- Document: At least two issues will need to be checked manually: logical reading order & color contrast.
- Logical reading order:
- Select the Order panel (it looks like a Z). If it’s not visible, right-click on the sidebar and select Order.
- You will see boxes that show the order in which the document will be read by a screen reader.
- If the reading order is incorrect, drag the items in the left-side Order panel until the content is in a logical reading order.
- When you are finished, right-click on Logical Reading Order and select pass. This places a green checkmark next to the issue.
- Color contrast: Do a visual check of the document. Look for background and text color combinations that make the text difficult to read. If there are no problems, right-click on Color contrast and select pass. This places a green checkmark next to the issue.
- Logical reading order:
- Alternate Text: there may still be issues, even after the Make Accessibility wizard has been run.
- Select the problematic item. When it’s clicked on, the checker highlights the item in the PDF.
- Note: if this error was fixed in the Make accessible wizard, right-click the item and select Skip Rule or simply ignore it.
- For additional information about an issue, right-click it and select Explain. Acrobat Pro will direct you to a webpage that outlines the issue and how to fix it.
- Once the errors have been fixed, right-click on the issue in the Accessibility Checker and select Check Again. This will place a green checkmark next to the issue.
- When all of the changes have been made, save the file and re-upload it to your website.
Watch the Purdue videos on:
- How to use Adobe Acrobat's Accessibility Full Check tool
- How to use Adobe Acrobat's Touch Up Reading Order tool
- Penn State. (n.d.) PDF Issues and Recommendations. Retrieved December 17, 2019, from https://accessibility.psu.edu/pdf/pdfissues/.
- WebAIM: Web Accessibility in Mind. (2019, April 25). PDF Accessibility – Acrobat and Accessibility. Retrieved December 17, 2019, from https://webaim.org/techniques/acrobat/acrobat.
- Kalbag, L. (2017). Accessibility for Everyone. Jeffrey Zeldman.
- Purdue University Innovative Learning. (2018, February 16). Making PDFs More Accessible Using Adobe Acrobat Pro [Video playlist]. Kaltura. https://mediaspace.itap.purdue.edu/playlist/details/1_ad5ov986/categoryid/86584511.