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Making PDF footnotes accessible

1 January 2010, updated 9 July 2010

Summary

The following sets out a method for making footnotes accessible in PDFs. A previous version of this article provided a solution for the tags output of a PDF, as read by screen readers and other assistive technologies (AT). This updated version solves the problem both for AT users and for those viewing a PDF in Reflow view. The latter includes users of small screen devices and those requiring large font sizes without the horizontal scrolling of normal page zooming.

The problem

Reading a document with a screen reader is a little like viewing it through a thin tube, one word at a time, and in a linear manner. It is not possible to jump from place to place randomly as a sighted person might, especially when reading footnotes. For this reason, in most cases, footnotes will need special treatment to ensure that they are accessible.

Editorial considerations

Before getting into the detail of how to fix PDF footnotes, worth a mention perhaps is that effective web copy is, generally speaking, short and to the point. But footnotes are the opposite, they provide fine detail. Leaving them out altogether or working them into the main body of content can improve readability significantly. They should therefore be used as sparingly as possible.

Creating footnotes in Word 2007

If you are using Microsoft Word 2007 to create your source document you won't have a problem accessibility-wise – it just works. Insert your footnotes in the normal way in Word and then generate a tagged PDF. Any footnote text will be read out by a screen reader immediately after its reference as if it were inserted inline rather than positioned at the bottom of the page.

However, if you are using any other program for your source document you will need to edit the tag tree of the PDF in order to make any footnotes accessible.

Creating footnotes in Word 2003

When you create a footnote in Word 2003 and then generate a tagged PDF, the footnote reference will automatically be linked to the footnote itself. The link can usually be followed easily enough and the footnote read.

However, there are still problems. Firstly, it is often hard for screen reader users to tell where a footnote ends, and therefore all too easy to continue into the next page (or the next footnote) without realising it. Secondly, even if it is possible to determine where the footnote ends, there is no easy way of getting back to where you came from in the main body of text. Either situation is likely to cause the reader to lose his or her place in the document.

Use a Destination?

Creating a link back from a footnote to its reference is possible using a PDF Destination (an in-page link much like an HTML anchor). However, doing so creates two new problems.

Sighted users don't need this additional link and may well be confused by it.
Destinations created in Acrobat will exhibit unexpected changes in page zoom settings that can be disorientating for sighted users. Destinations created in InDesign have no such zooming problems, but the problem of how to get back to your starting point remains.

Fortunately, there is a simple solution which requires just a quick edit in the PDF's tag tree.

The objective

The following tag tree edit will change the position of a footnote in the document's reading order for AT users only. It will no longer be positioned at the bottom of the page but will instead appear inline (at the same point previously occupied by its reference). At the same time, the footnote will remain at the bottom of the page in both the standard on-screen or printed view (the "document view") and in Reflow view.

Tag
tree showing link tag and footnote tag out of place.

Figure 1

The method

Note: the content in the source document that generated the first few tags in Figure 1 was:

"(Popular myth number 1): humans use only 10 per cent off their brains.¹"

Also note that the following process describes a tag tree generated from a typical Word 2003 document. An InDesign-originated document will be similar but there will be no <Link> or Link–OBJR tags to delete (steps 2 and 3 below).

In Acrobat Professional, open the tags panel (View – Navigation Panels – Tags).
Locate the <Link> tag associated with the footnote reference. The <Link> tag will have two child tags – a content container for the footnote reference and a Link–OBJR tag (see Figure 1).
Delete the <Link> tag (its two child tags will also be deleted).
Click the <Footnote> tag (shown near the bottom of the tags panel in Figure 1) to select it.
Drag the <Footnote> tag and drop it in the required location – in this case, the location previously occupied by the <Link> tag (see Figure 2).

Tag
tree showing link tag and footnote tag in the correct place.

Figure 2

Note: The above assumes that the footnote reference appears at the end of a paragraph and that there is a convenient place already existing in the tag tree to move the footnote tag to. If this is not the case, if, for example, the footnote reference appears in the middle of a paragraph, then select the text either before or after it and then select Create tag from selection in the Options dropdown of the tags palette. This will break the paragraph into separate tags and allow you to insert the footnote tag in the appropriate place.

Identifying the footnote

There is one further enhancement that will make the footnote even more accessible than the Word 2007 version, and that is to alert the user that this piece of content is a note rather than part of the main body copy.

To do so:

In the document panel, highlight the footnote text and copy it (Ctrl + C).
Right-click the <Footnote> tag and from the context menu select Properties.
Paste the footnote text into the Alternate Text field of the TouchUp Properties dialogue box.
Type "Note:" before the footnote text and "(end of note)." after it.
Close the TouchUp Properties dialogue box.

The result

Footnotes edited in this way will be identified as notes by ATs and will appear in the right place in the reading order (that is, in context). However, they will remain at the bottom of the page for standard document view and for Reflow view. In addition, the footnote references will not be picked up by ATs. In Word-originated documents their tags will be deleted and so rendered invisible to AT users. In InDesign the references should be tagged as Artifacts to produce the same result.