If the contents of a PDF are not tagged appropriately assistive technology users have no reliable means of navigation. Tagging text into paragraphs and headings as they appear on the physical page provides Assistive Technology (AT) users the same awareness sense of hierarchy or structure as visual users so they can more easily navigate the material.
Headings are especially important, as without headings PDF documents can be almost un-navigable, especially longer and more complex documents.
Headings provide organization and structure. Imagine a document without a table of contents (TOC), all text at the same font size and arranged as a series of paragraphs. It would be necessary to skim each word just to locate a small bit of information, and frustration levels would be pretty high. This is the experience of an assistive technology user when confronted by a PDF file without consistent headings.
Although there are no requirements pertaining to headings in the existing Section 508 regulations, certain organizations such as the US Health and Human Services (HHS) administration require them for accessibility.
The biggest question is not how but when text should be tagged as a heading. An obvious answer is “if it’s bold and larger than other text,” but this may not be correct in all cases because font style and document structural elements are not the same things. Headings serve a function; in accessibility terms, they provide a means of navigation to major portions of a document. Don’t make all text with large or bold fonts into headings – it’s important to use headings consistently and reflect the real structure of the document.
Headings serve to provide a title or announcement for the content that follows. Practical examples of headings include chapter and section titles of a document.
Headings must be used consistently and logically throughout the document. If a chapter title is set as Heading 1 <h1>, then all chapter titles in the document need to be set as a Heading 1. Because the chapter is a Heading 1, then the first major subsection of the chapter should be Heading 2. A jump from Heading 1 to Heading 3 should be avoided. The heading structure provides an outline of the content to AT users, so accordingly, the outline’s hierarchy should be nested and descend without jumping levels.
There are three basic methods of tagging content as a heading, but the first step is to always select the relevant text runs. Then, do one of the following:
- Use <CTRL>+<1-6>. This keyboard shortcut will take the selected text and place it into a heading tag. The number you use determines the heading level. For example, <CTRL>+<2> will tag the text as an <H2> heading. Remember to reserve <H1> for the document title.
- On the Insert menu, click More. Select the correct heading level from the drop-down menu. If you are prompted for shared or individual parents, select shared to place all of the text runs into one heading tag.
- From the Add Heading menu in the toolbar, select the appropriate heading level. If you are prompted for shared or individual parents, select shared to place all of the text runs into one heading tag.
It’s also possible that the text runs are grouped correctly into paragraphs and headings but the heading level is wrong. To change a tag, set the Selection tool to Exact. Select the tag.
There are three ways to convert a tag after it has been selected:
- Use <ALT>+<1-6> to convert it to a heading. (<ALT>+<7> will convert the tag to a paragraph).
- From the Edit menu, click Tag Converter. Select the correct heading from the list.
- Click the Properties tab located in the physical pane. Click in the Type field. Click the box that appears on the far right. Select the correct heading level.