InDesign uses styles, similar to the way HTML pages use cascading style sheets (CSS). With InDesign styles, you can keep the semantics and structure of the document mostly separate from its visual appearance. You can apply a single style to many parts of the document, streamlining and simplifying the task of ensuring visual consistency throughout the document. If you need to change the appearance—by switching to a different font, for example—you would change the style, which would update all locations where that style is applied. You would not have to update all of the individual instances of that font within the document.
All of this is true, no matter where you use InDesign styles, but it is especially important to use InDesign styles for headings because headings can be mapped to tags (h1, h2, h3, h4, h5, and h6) that screen readers can interpret. The purpose of this is to supply visually impaired users with the same scanning and navigational tools that sighted users’ experience by being able to quickly recognize headings and find the information they are looking for without having to listen to an entire document being read aloud from top-to-bottom.
Use Headings to Create a Logical Outline
One of the most important things you can do for document accessibility is to use the heading structure appropriately. The goal is to use the headings to create a logical outline of the content. If you could extract just the headings from the document, they ought to stand alone as an overview of the organization and content of the document.
Most documents can be represented with a level 1 heading to identify the title and at least one or two level 2 headings. Lengthier documents should typically have many more headings than that in order to simplify navigation with or without a screen reader.
Screen Reader Users Can Navigate Documents by Headings
Screen reader users can navigate the headings in documents, jumping from one heading to the next, listening to the heading hierarchy, and forming a mental map of the content in the document without having to read it all. The heading structure makes the document easier to understand.
Being able to listen to the heading structure before reading the document is also a tremendous time-saver because it lets screen reader users jump to the section that they’re most interested in.
Headings Can be Visually Styled in Many Ways
If you’re worried that using headings will make your documents look too formulaic or boring, you can set that fear aside. You can style your headings any way you like, changing the font, color, size, and a long list of other properties. Knowing this, when you think about headings, remember that appearance is not as important as the structure they provide.
Map the Headings to Headings Tags
Big bold text doesn’t count as a real heading unless it is mapped correctly! A heading in InDesign isn’t really a heading until it has been mapped to a heading tag. Here is the process for creating a style and mapping it to a heading tag:
- Open the paragraph styles panel: Type > Paragraph styles.
- Create a new blank style: Select the New Style icon (in the bottom right corner).
This will add a new style to the list of styles in the main pane.
- Open the style editor: Double-click on the new style.
- Assign a name to the style: In the General category, type a Style Name
Tip: It can help to add the level of the heading to the style name, e.g. “Instructions H1,” or simply “H1”. It’s easier to remember the accessibility purpose of each style that way.
- Modify the style’s visual appearance as desired (font, position, margins, etc.).
Tip: Not all headings of the same level must look the same. You can create multiple H2 styles for example.
- Assign the Appropriate Heading Level: In the Export Tagging category, go to the PDF Tag selector and choose H1 or H2 or H3, etc. Do the same for the EPUB selector.
- Click “OK” to exit the dialog.
Apply the Styles to the Document
Now that you have a heading style available, you need to apply the heading to the text. Put the cursor on the text in the document, then select the appropriate heading level from the Paragraph Styles pane. The text will change to match the visual styling associated with that InDesign style, and InDesign recognizes the underlying mapping to the heading tag, even though the tag itself is invisible.
Avoid the Formatting Toolbar for Most Things
For nearly everything you do in InDesign, you should avoid using the paragraph and font formatting tools (shown below) in the Control toolbar if at all possible.
It is tempting to use the formatting toolbar because it is easy to find, and it allows you to make direct changes to the objects on the page, but it bypasses InDesign’s styles, which can lead to problems in visual consistency, and which can bypass the accessibility features of the document. The formatting toolbar is the “quick and dirty” way of modifying the appearance, but avoiding it may actually save you time in the long run, especially on lengthy or complicated documents.