Paul Rayius

PDF Tagging and Reading Order  

This is the first of an eight-part series on PDF Accessibility


Making sure that PDFs are accessible to everyone, including those using assistive technologies like screen readers, refreshable braille displays, screen magnifiers, etc., can be a daunting technical process. In this article, we’ll address two basic PDF accessibility concepts – tagging and reading order. Then, in subsequent articles, we’ll address more specific topics in PDF accessibility. 

What is a Tagged PDF?

Tags in a PDF are similar to simple HTML code; paragraphs of text in a PDF go into <P> tags, images go into <Figure> tags (more details about this in a future article), heading text goes into <H> tags. These heading tags are numbered H1, H2, H3, and so on, to show the document’s organization, structure and hierarchy.  

Tags add behind the scenes coding to a PDF, so they can be read by assistive technologies (AT). When these assistive technologies read PDFs to people, they read the information from the tags. Therefore, if a PDF isn’t tagged, there’s basically nothing to read. This is why properly tagging PDFs is critical. 

There are other tags that may be used such as <Table> with table row, header, and data cells inside, <L> (list) with <LI> (list items) containing label <Lbl> and list body <Lbody> tags. For this article, we’ll keep it simple.

How to Tag a PDF 

Adobe Acrobat Pro is the best tool PDF tagging. Using Acrobat, there are a couple of ways to go about tagging a PDF. One way is to use their Reading Order tool (in earlier versions this was known as the Touch–Up Reading Order or TURO tool). 

The tool offers an effective way to tag things like paragraphs, headings and figures. If used correctly, it can ensure the reading order is accurate, but this tool has its limitations. Some repair work—also known as remediation—is probably going to be needed once the tagging is done.  

The other way to add tags in Acrobat is to simply navigate to and open the Tags pane. From here you can either right-click on No Tags available or select it and then use the keyboard to open its context menu. Choose Add Tags to Document

Acrobat will do its best to “look” at what’s going on in the content of the document and assign the best tag option to that content. It will also try to determine the correct reading order for the tags.  

While Acrobat has put a lot of development time and money into improving their tagging capabilities, this method isn’t perfect. There will still need to be some remediation work done. While both of these methods are for tagging individual PDFs, one at a time, Acrobat can tag PDFs in bulk, too. 

Reading Order?! 

Congratulations, you have tagged your PDF. Now, what is reading order and why is it important?  

When it comes to accessibility, the reading order in a PDF is literally the order in which content in the document will be read to people using assistive technology. AT can only read PDFs accurately and logically if the reading order is correctly established. This is done with the tags; whatever order the tags are in is the order in which the content of the document will be read (unless people use functionality in the AT to navigate through the document differently).  

You can see why checking the accuracy of the reading order in the tags is a crucial step in PDF remediation. It’s also one thing that many people get confused about – and Acrobat’s not very helpful here, either. Many people are under the impression that they can use the Order pane in Acrobat to fix the reading order of the PDF, but that’s not the case. Because AT reads from the Tags, we need to use tags to fix reading order issues.  

How Do I Fix Tags and Reading Order? 

When fixing the reading order in a PDF, you essentially have two tools at your disposal: Adobe Acrobat and CL PDF. Fixing the tagging in Adobe Acrobat can be a very confusing, time consuming and frustrating task. CL PDF is the professional’s tool for the job. CL PDF has advanced features and functionality built-in to make the job faster, easier, more efficient and less error-prone. And, unlike Acrobat, if you make a mistake, there’s an Undo option. This feature alone saves time, energy and frustration.  

How We Can Help

We hope this helps shed some light on the basics of PDF tagging and reading order. If you would like to know more, email us at We have the software and the training to help you do it right yourself. Or you can use our Remediation Services to do the work for you. You can even do a combination of the two. For example, our remediation team takes care of the bulk of the work now while you learn how to use our software to take care of things in-house moving forward. Any way you want to approach your PDF accessibility needs, Allyant is here for you.

Read the Entire Series Here

Step 1: Tags & Reading Order

Step 2: Metadata

Step 3: Color & Contrast