When creating an accessible PDF, you should begin with the source document whenever possible. Modifying the original is easier and faster. It doesn’t necessarily mean it will fix all the errors, but it’s easier to fix as many as possible in the source document first. Follow the process of creating an accessible PDF from Word and choose the correct export settings.
Adobe guidance
Make sure you have the latest version of Adobe Acrobat Pro DC installed on your computer.
Adobe has in-depth pages on creating and repairing accessible PDFs in Adobe Acrobat Pro DC.
Setting up Acrobat
Make sure you have the latest version of Acrobat Pro DC installed to access all the accessibility options.
Follow these steps to set up Acrobat ready to check documents:
- select Tools in the task bar at the top of the screen
- scroll down to the Protect and Standardise section
- select the drop-down under Accessibility and select Add shortcut
Skip this if you have already set up Acrobat on your computer.
Checking PDFs for accessibility
Running the accessibility checker can help us locate common accessibility issues that may be occurring in our document. It won’t find everything, so after running the checker, we need to perform a manual check too.
To check your document for accessibility:
- select Accessibility from the right-hand menu. This will bring up the Accessibility menu
- select Accessibility Check to open the Accessibility checker options panel
- ensure the Create accessibility report box is not ticked
The report will appear on the left of the screen and highlight any issues with the document, any areas with issues will be highlighted in bold and have a bracketed number after them.
- right-clicking on an issue will open a dialogue box with guidance to fix the issue
- make sure you fix the title and primary language as MS Word often misses these
Tagged PDF
Acrobat does have an autotag feature that can add tags to your document. However, the autotag feature can be inconsistent and unreliable, and you will end up spending more time correcting its mistakes then you would have spent adding tags manually. Adding tags one at a time is very easy to do, and it exponentially increases your chances of having a fully accessible PDF.
This video looks at how to tag a PDF document.
Bookmarks
This check fails when the document has 21 or more pages, but doesn't have bookmarks that parallel the document structure. This video looks at how to make bookmarks accessible in a PDF document.
Headings
When the accessibility checker flags a headings issue, it is usually because one or more of the headings are not nested properly. You could have a Level 3 heading directly beneath a Level 1 heading, with no Level 2 heading in between them. Or maybe your document begins with a Level 3 heading, but it has no Level 1 or 2 headings at all. That kind of structure can be confusing to people who use assistive technology, because they often rely on headings to jump from one part of the document to the next. If the heading structure doesn't make sense, then the document will be very difficult for them to navigate. That's why the accessibility checker flags headings that are not nested appropriately.
This video looks at how to make headings accessible in a PDF document.
Images
If the accessibility checker flags “figures alternate text,” this means that one or more images in the document do not have text descriptions in their tags. People who navigate the document using screen readers won’t be able to make sense of the images unless you give each image a text alternative or mark it as an artifact.
This video looks at how to make images accessible in a PDF document.
Colour contrast
Our advice when it comes to using colour in your documents would be to stick to black and white. If you do choose to use colour in your documents, remember that you can’t use any colours to infer meaning. For example, using red to imply danger or green to imply a good result for example. Someone who is colour blind can’t pick up on this.
Checking for colour contrast has to be carried out manually. It alerts you to instances where text is not readable against its background (for instance, where a user is colour-blind).
This happens when text is not different enough in colour to the background but also if text isn’t large enough. Large text is defined as 18 point (typically 24px) or 14 point (typically 18.66px) for bold text.
To check a PDF for colour contrast, you want the hexadecimal or RGB values of the colours used in the document.
If these are available then the online tool WebAIM colour contrast checker is an easy-to-use tool.
Copy the text colour code into the foreground colour box and the background colour into the background colour box.
If the colours result in a green pass next to WCAG AA then the colours are good to use.
If you don’t have the hexadecimal or RGB codes, you can use the Paciello group Colour Contrast Analyser.
This tool has a colour dropper which can be used to sample the colours used in the document. The text colour should be input to the foreground colour box and the background colour should be input to the background colour box.
If the colours result in a green pass next to WCAG AA then the colours are good to use.
This video looks at how to check the colour contrast in a PDF document.
Reading order
Screen readers will announce the content in my PDF based on the document’s tags. The order in which the tags appear in the tags' panel is the order in which the content will be announced. Not only is the ideal reading order left-to-right and top-to-bottom, but it should also match the visual flow that a sighted user will experience. These things aren't always the same.
This video looks at how to determine that the reading order in a PDF document is logical.
Navigation links
This involves ensuring the links in your PDF document are descriptive, and unique. This video looks at how to make navigation links accessible in a PDF document.
Lists
There are 2 types of lists. Ordered and unordered lists. Ordered lists use numbers or letters, while unordered lists use symbols. In PDF files, both types of list are tagged the same way.
This video looks at how to make lists accessible in a PDF document
Tables
Tables shouldn't be used for text layout, only for data. The reason is that screen readers will read the content of a table in a linear fashion - left to right, top to bottom. This means tables can’t be scanned vertically up and down by column, or diagonally, or from one row to another 2 rows down, skipping a row, by people using screen readers. So they are not a useful, or an equal way of presenting information for quick comparison for those users.
Header cells (TH) appear at the beginning of a column or row, and they categorise the the content for us. Data cells (TD) are the individual pieces of information in a table, and they are grouped by one or more headers. (Blank cells can be marked as data cells, too.) When screen reader users move between table cells, they are told which header each cell is associated with. However, if a table is not accessible, then they are not told this information.
This video looks at how to make tables accessible in a PDF document.