Paul Rayius
VP of Strategic Accessibility | Customer Success & Training
Defining Accessibility in the Digital Space
I often talk with people who are not in the accessibility space and, as such, I’ve learned that I need to, sooner than later in the conversation, define what accessibility is. Many years ago, I was at a conference, standing at the company booth, when the director of a hospital walked by. I started chatting with him, asked him what he did, and whether or not they use PDFs at the hospital (of course, they do). The obvious follow-up question was, “Are your PDFs accessible?” He said to me, “I don’t know; I can find them whenever I need them.”
Clearly, different people have different perspectives on what the term accessibility even means! So now, when people ask me what I do, I tell them I work for a software company and, we make PDFs accessible for people who are blind, visually impaired, or have other disabilities. That one sentence, I’ve learned, quickly defines what I do and clarifies what I mean by accessibility. And, quite frequently, the follow-up response is, “how does someone who is blind read a PDF?” Gotcha! Thanks for asking!
The Foundation: What Makes a PDF Accessible?
It turns out, though, that even within the accessibility “space,” people often ask, “How do you make a PDF accessible?” Or, specifically, “How do you make a PDF accessible for screen reader users?” There’s a lot that goes into it, but I’ll try to boil it down into some manageable pieces.
However, before I do, I think it’s also worth pointing out that if a PDF is accessible for someone using a screen reader, it’s likely accessible to many other user-groups as well, including people who are visually impaired and using assistive technology, people who have motor problems and require keyboard, or other, navigation, people who are using refreshable braille displays, and more. And, at the same time, there are things in a PDF that a screen reader (or other assistive technology) might handle just fine that present issues to other user-groups. I’ll touch on some of those, too.
The Secret Behind the Screen: PDF Tagging
So, what makes a PDF accessible for screen reader users? Tags, or tagging, in the PDF is a big first thing. Even though the software might be called a “screen reader,” when it comes to PDF, it’s not actually reading from the screen. It’s reading from a behind the scenes layer in the PDF, from the Tags (also known as the tags tree or the structure tree).
So, if there aren’t any tags in a PDF, there’s basically nothing there for a screen reader to read. The screen reader will read things like the file name and maybe some other metadata but that’s really about it. Some screen readers will try to read content in the PDF from other behind the scenes layers but… that goes against the accessibility requirements and comes with varying degrees of success – or lack thereof.
Rule #1: The Importance of Correct Semantic Tagging
Rule number 1 for PDF accessibility is that the PDF has to be tagged. But it’s important to know that the mere presence of tags is not enough! Content has to be tagged correctly, and those tags have to be organized logically so that, when they are read, the flow of the content makes sense! But what do I mean by tagged correctly?
PDF accessibility requires that the most semantically appropriate tag is used for the content. What!?
Basically, if something looks like a heading on the page, it should be tagged as a heading. Paragraphs of text should just be tagged as paragraphs. Lists need to be tagged as lists. And here’s one that might throw you – data tables need to be tagged as tables but if something is not a data table then don’t tag it as a table. In other words, while authors might use the table functionality in the authoring application to help them format stuff on the page, in the PDF, if that content isn’t really tabular data then it should not be tagged as a table!
| Tip: To see how this works in practice – from auto-tagging to manual fixes and full batch processing – watch Paul’s step-by-step tutorial using PDFix Desktop. |
Enhancing Navigation: Headings, Lists, and Data Tables
But why? What do the tags really do? As previously mentioned, the tags hold the content that gets read by a screen reader. But the tags do so much more. Tags convey structure and relationships in a PDF, and they help screen reader users navigate through the document in a number of ways.
Take headings, for example. The use of different heading levels informs the screen reader user if they are in a major section of the document (heading level 2, for example), or if they are in a sub-section of a document (a heading 3, for a sub-section within that H2 section, for example). Furthermore, headings provide an efficient and accurate way for screen reader users to navigate to a particular section in a document. A screen reader user can pull up a list of headings, read through that list, and then navigate to the part of the document that they want to read without having to read through a bunch of stuff they don’t care about, first!
When used correctly, lists and tables provide similar navigation functionality. When a screen reader user comes across a List tag in a PDF, they will be told “List of ‘X’ (number of) items.” Then, they can read through the list, navigating up and down through the items, and they are told when the list has ended.
Similarly, with data tables, screen reader users can not only navigate up and down through the rows in a table, but they can also navigate across the columns – assuming that the table has been tagged correctly – and, of course, this is one huge reason to not tag something as a table when it’s not really a data table!
Managing Visual Elements: Alt Text and Reading Order
Similar to websites, images that convey important information not only need to be tagged but they also need Alternative text, so the screen reader has something to read. The Alternative text should accurately tell screen reader users what is important about that particular image.
And, of course – there’s also stuff that should not be tagged. What shouldn’t be tagged? Anything that doesn’t need to be read by a screen reader. Examples include decorative images that don’t convey anything important and the line on the page that separates the main body from the footnotes (although, to be clear, the footnotes need to be tagged!). Repeated headers and footers… should only be tagged once – not as they repeat on every page! There are perhaps other things that should not be tagged, too.
| The important thing to remember is that anything that conveys important information needs to be tagged and anything that doesn’t convey important information should be untagged. But this also brings me to the next major piece. |
Establishing a Logical Reading Order
Not only does content need to be tagged correctly but also, as previously touched on, those tags need to be in the correct reading order so that, when someone is using a screen reader (or other assistive technology) it’s reading through the document in a logical manner, as the author intended.
Sometimes establishing a logical reading order is easy. Sometimes the reading order can get trickier like when the page has multiple columns of text – or, in a newspaper, for example – when an article starts on one page but then continues somewhere else.
One of the nice things about tagging and reading order is that we can move tags around in the Tags tree, so the content flows in a logical manner, and doing so doesn’t change how the PDF looks!
Beyond Screen Readers: Color, Contrast, Font Size, and Visual Accessibility
In a nutshell, when it comes to PDF accessibility and screen readers, that’s pretty much it – make sure the correct tags are used for the content (and they are being handled correctly), and make sure the tags are in the correct logical order. However, I would be remiss if I wrote an article on PDF accessibility and didn’t mention some other things.
Because – when it comes down to it – PDF accessibility is more that just “how a screen reader will read it.” We also need to pay attention to color use, ensuring color – or other visual cues – aren’t the only ways information is being conveyed. Also, while a screen reader might read vertical text on the page just fine, someone with visual or cognitive limitations may struggle with vertical text. Similarly, a screen reader doesn’t care how small the font size is but someone who is visually impaired sure might! And, of course, contrast is an important consideration as well – making sure that the content on the page can be easily seen, and it doesn’t blend into the background!
Next Steps for Your PDF Accessibility Strategy
I hope this article provides a good overview of PDF accessibility and what’s needed from the screen reader user’s perspective. And, of course, if any of this is confusing, or if you need help on how to actually do any of this, just reach out to us. We’re here to help you, and we’re here to work with you, to ensure your audience can read your PDFs successfully!
