Creating accessible indesign / PDF files - 'Appropriate nesting - Failed'

[lewkeo]

HI all,

I'm trying to build an accessible PDF in indesign. I want to create the indesign source files as best as I can in terms of accessibility, so that it doesn't require any more changes when put through the Acrobat Pro DC Accessibility Checker.

I have been getting the error 'Appropriate nesting - Failed' when i run the Acrobat accessibility check and can't work out why. It flags up one or two headers, in this instance two H3 headers were causing issues. I found a workaround fix... I duplicated the paragraph style and created 'H3 alt'. This seems to fix it, but I don't understand what causes this error. Ideally, I don't want to have to create alt styles when it works for some headers and not for others.

Any ideas?

Thanks guys

Lewis

[hammer0909 · Accepted solution]

You'll get this error if you skip heading levels in your document. What I mean is, for accessibility your first heading that appears in the tag structure should be H1. After that you should have an H2. If you skip from H1 to H3 or H2 to H4, you'll get the error that you receive. Go back and look at your PDF file and figure out where it skips then edit the export tags in the InDesign file to properly reflect the heading structure that you need.

This can get tricky because print designers often use Heading, Subhead, Subhead B, etc to identify headings and then often will randomly use a Subhead B because it looks good visually but for accessibility it could cause the issue you encountered because your skipping a logical heading sequence in your file. I find sometimes I need to duplicate the Subhead B style (or any other style for that matter) and assign it a different export tag so that it exports correctly.

Here's an example of how your heading sequence should look:

Heading 1

     Heading 2

          Heading 3

     Heading 2

          Heading 3

Heading 1