PDFs & Accessibility
Making your web content accessible to anybody who wants to read it is very important.
Visually impaired people use screen reading software such as JAWS, Window-Eyes or Voiceover (Apple only) to get the information they need, so we need to make sure our content can be accessed using screen readers.
Text on a web page is easily picked up by screen readers searching the HTML code. However, our web pages also contain many links to documents – PDFs (Portable Document Format) being the most common and most suitable for the web.
It is a common misconception that PDFs cannot be accessed by visually impaired users. In fact, PDFs can be made fully accessible.
How to Make Your PDF Accessible
Tagged documents provide the best reading experience for screen reader users. When a PDF has been tagged, screen readers do a better job of interpreting the document’s structure and reading order.
You are able to tag your PDF if you are using Adobe Acrobat 8.0 or above. This software will need to be purchased if you do not already have it installed. Please contact ITS for more information or visit https://www.adelaide.edu.au/its/software/adobe/ .
Note: The instructions below use Adobe Acrobat 9.0. Other versions may vary.
Adding a Document Title
If your PDF does not have a document title in the metadata of the document, then your PDF is not fully accessible.
A document title is helpful to quickly communicate the purpose or topic of the document. When a title is not available or does not match the content, the reader may need to invest more time to determine the topic of the document and to decide whether the document contains relevant information.
To add a document title, follow the W3C instructions .
Creating and Editing Tags
Open your PDF and go to Advanced > Accessibility in the toolbar. If Add Tags to Document is greyed-out, tags have already been added to the document.
If you know your document contains tags, you can then select View > Navigation Panels > Tags from the toolbar. This will display a pop-up box showing you all of the tagged content within the PDF.
To edit existing tags, right-click on a tag and select Properties from the drop-down list. This will allow you to edit the tag. For example, if you have an image tagged, you can add alternative text etc.
Create New Tags
If you go to Advanced > Accessibility and Add Tags to Document is highlighted (see image below), click this and Acrobat will automatically add some tags, however these are likely to be insufficient in order to make your PDF fully accessible.
You will then be able to see a Recognition Report on the left-hand side of your screen (see image below). This summarises your content and tells you what may need fixing to make the PDF fully accessible.
Keep the Recognition Report open and again click on the Advanced tab > Accessibility > and this time select TouchUp Reading Order.
This will display a pop-up box showing a number of content options.
Your cursor will then allow you to draw an outline around a specific piece of content and select one of the appropriate content buttons. For example, if you outline an image on your document, you would select the ‘Figure' button. You can then right click on the image and select ‘Edit Alternate Text' to add the image description which will be read out by the screen reader.
When you're done, click Close.
Changing the Reading Order of Your PDF
The reading order of the PDF is of particular importance to those using screen readers. If your order is not correct, the document won't make any sense. Go to View > Navigation Panels > Tags > Order. This will show you the order in which your content will be read.
To move your reading order, simply select the tag and drag and drop to the required point in the list.
Check Your Document's Accessibility
To check if your PDF is fully accessible, go to Advanced > Accessibility > Quickcheck. This will show you a high-level results view. If no problems are detected, it may advise you to choose to do a full check.
To do a full check, go to Advanced > Accessibility > Full Check. Here you can change your accessibility options. Click Select all under the Checking Options section to be fully accessible and click ok.
If elements of your document are not accessible these will be shown in a pop-up box. When the pop-up closed, an accessibility report opens on the left-hand side and shows you what issues are remaining how to fix them.
Once these issues have been fixed, you'll then need to resave your document.
For more information, please visit: http://www.adobe.com/accessibility/products/acrobat/training.html .
PDF Accessibility Checker
To check the accessibility of your existing PDF document, you can use this PDF Checker . It allows you to check the PDF by URL or by file upload and will highlight any accessibility issues with your PDF, and how to fix them.
Selecting the Language of Your PDF
While it is obvious to most readers which language your content is written in, it may not be so obvious to screen reader software. So to minimise any problems with assistive technology recognising your content, you'll need to select the standard language of the PDF.
Go to File > Properties > Advanced tab and select the language of document under the Reading Options section and click ok.
Are Scanned PDFs Accessible?
No. Documents that have been scanned and saved as a PDF are not accessible. To make the PDF accessible, you first need to make the content searchable within Adobe Acrobat.
Click on the video tutorial link below which shows you the best way to make your existing scanned PDF accessible using Adobe Acrobat 8.0:
Is PDF Content Accessible to Visually Impaired Users Without a Screen Reader?
Yes. If users don't have screen reading software installed, they are still able to access the text in your PDF document by downloading Adobe Reader 9.0 or above.
Adobe Reader is free to download from http://get.adobe.com/reader/ and provides users with the ability to have the content of your PDF document read out to them.
For users to hear the text from your PDF, they can select View > Read Out Loud from the toolbar. This gives them the option to either:
- have the text read line by line
- read the content page by page
- read the whole document.
Are Untagged PDFs Accessible?
To a degree, but they are not fully accessible.
Automatic tagging helps solve the problem of untagged PDF documents. Adobe Reader can analyse an untagged document and add temporary tags to sort the reading order for screen readers. However, these tags may not be specific enough and won't add ALT tags (image descriptions) to your images.
Because this is a temporary fix which happens each time the document is opened, it may take longer for the document to download. That's why it better if you tag the PDF in the first place.
How do Screen Readers Access the PDF Content?
Screen readers are able to interact with Adobe Reader to access your PDF content. Users can follow the SetUp Assistant within Adobe Reader to control how the document displays and how the content is delivered to them.
The World Wide Web Consortium (W3C) have developed some PDF Techniques for WCAG 2.0 guidelines which provide more information about creating accessible PDFs.