When building or creating your document, you should have accessibility in mind the whole time. It is much easier and less time consuming to create an accessible document from the beginning than it is to deal with fundamental fixes after the fact. Even then, when you convert that original document to the PDF format, you’ll need to follow up with special accessibility tools to make sure your PDF document is compliant. Using best practices in your native authoring software will minimize that second level of work by helping create the proper tags in the final PDF.
Tags appear in what is known as a “tag tree” within PDF editing software (typically Adobe Acrobat Pro DC). The tag tree shows the structure of every element within the PDF in a hierarchically arranged list. The tags within the tag tree help assistive devices interpret the structure and elements within your document and preserve the layout of the PDF document. They are critical to promoting content perception, easier navigation, document usability, and greater understanding. They can also be finicky, so addressing tagging issues during the content creation process can save you tag remediation headaches later.
When thinking about the content for your document, there are a few questions you should ask yourself. Is the content relevant and does it add value? Is the information organized logically under easy-to-understand headings? These questions will help remove unnecessary information, supporting understandability. When you have information that is just filler, it can be confusing to use a screen reader to navigate through the filler to get to the meaningful content.
Always use the authoring software’s internal structures to set up your document using programmatically styled heading levels (e.g., “Heading 1,” rather than tweaking your text font to be “Times New Roman paragraph text, bold, size 16.”), lists, tables, etc. This will ensure the foundational structure is set up when you are tagging your PDF in Adobe Acrobat Pro DC. Structure allows the user to navigate the content efficiently.
Color contrast is important for people with lower vision or colorblindness. Color contrast should be checked from the beginning of your document creation. Color contrast isn’t subjective, either. Color contrast is based on numerical values that relate to each color and are compared to each other. If the comparison conforms to the appropriate ratio (which differs for small or large text), there is adequate color contrast. If it does not, even if you think it looks fine, it fails color contrast standards and is out of compliance.
All images—photos, charts, diagrams, logos, illustrations, etc.—need adequate alternative text. Alternative text explains images for non-sighted users. A screen reader will use the textual information tied to the image tag to explain the image. If the image does not add value to the content, but is simply decorative, you can declare it as such using the procedure for the particular authoring software you are using. In Acrobat Pro, you can tag decorative images as “background” in the final PDF so the screen reader will just skip over it.
All documents need to have certain properties designated for assistive technology to work correctly. Each document needs the language of the document set so the assistive technology can read it correctly. This can usually be designated in the native authoring program, but should also be checked in the final PDF.
Also, assuming the structure of your document is logical in your native program, and that you’ve created your structure properly, there may be settings in your authoring software that help carry your structure to the PDF format. Otherwise, in your PDF, you will need to set the tab order for the document to follow the structure of the document you laid out. Having this tab order set properly affects how a cursor travels through your document, and the order in which your content is read.
Finally, when the PDF is set up you will need to mark the document as a tagged document if that did not happen upon conversion. If content isn’t tagged, a screen reader will not be able to read the content in your document.
The reading order of a document is probably one of the most important things to remediation. This order is a road map for the screen reader to follow the correct path of your content. For Word documents, the reading order is usually left to right, top to bottom. However, sometimes there are text boxes or columns that may require a different reading order. More complex layouts in Adobe InDesign can also vary, as can content within PowerPoint presentation slides. The language in which content is written can also require a different reading order. For all these reasons, it’s important to make sure that you create your original file logically. However, Adobe allows you to set the order in the final PDF, though it may take making adjustments.
Adapted from Testing and Remediation Strategies for PDF Accessibility, a training course from Mircoassist.