Multi-column PDF reading order: sidebars, footnotes, tables and complex layouts

Multi-column PDF reading order is where accessibility problems hide in newsletters, annual reports, budget books, brochures and agenda packets. A screen reader follows the tags, the hidden structure that tells assistive technology what each part of the page is and in what order to read it. On a designed page, those tags often follow the order in which things were placed rather than the order a person reads them, so columns interleave and sidebars cut sentences in half. This guide is a pattern gallery: ten common layouts, what a screen reader user often hears, the order that works, and how to tag it. Where more than one order is reasonable, it gives a sensible default and says the call is yours. For tag order, content order and Acrobat's manual check, start with logical reading order in PDFs.

Why multi-column PDFs read out of order

When a PDF is tagged, by the program that exported it or by an auto-tagger, software infers the order from where things sit on the page. A one-column memo usually comes out fine. A designed page often does not.

• Content often sits in the order a designer created it, so a pull quote added last can land anywhere.
• Text boxes and floating images sit apart from the story they belong to.
• Tagging that reads across the page can follow a line in column one with the line beside it in column two.
• Paragraphs split across columns or pages, so reading halts mid-paragraph, a problem the University of Illinois Springfield's accessibility guide calls out.

These errors land hardest on screen reader users, and also affect people who read in Reflow view or with magnification.

Ten layouts and the order a screen reader should follow

Tag names below are standard PDF tags. Art is short for article, a self-contained story. It is not the same thing as an artifact, which is content marked as decoration so screen readers skip it.

How to tag columns, sidebars, pull quotes and continued stories

Two- and three-column text

W3C's guidance on criterion 1.3.2 describes the natural order of a multi-column page: top to bottom of one column, then the top of the next. A headline that spans the columns comes first. When a paragraph breaks at the bottom of a column, the tags should carry the reader straight into the rest of it. Acrobat's Reflow view (View, Zoom, Reflow) makes interleaved lines easy to spot.

Sidebars and callout boxes

W3C's own example for 1.3.2 is a magazine article with callout sidebars, and it says: "The order of the article and the sidebars does not affect their meaning." So the position is the author's call. A sensible default is right after the paragraph the sidebar relates to, or at the end of the story if it stands alone, and never mid-sentence. Group the box's heading and text in one container so it is read as a unit, and give its heading a level below the story's. PDF 2.0 added an Aside tag for sidebars. A PDF 1.7 file has no Aside, so use a Sect.

Pull quotes

A pull quote repeats a line from the story in large type, so a screen reader user hears it twice, the first time out of context. If it repeats body text word for word, mark it as an artifact. If it contains words that appear nowhere else, such as a resident's quote missing from the story, it is content: tag it as a paragraph and place it at a break, like a sidebar.

Stories that jump to a later page

Newsletters often run "continued on page 4." The tag tree does not have to follow the pages. Put the continuation directly after the first part, inside the same story container, so the story reads straight through. The jump lines can then be marked as artifacts or left as text to match the print layout. Either is defensible.

Where captions, footnotes and page numbers belong

Figures, captions and charts

A caption belongs right next to its figure, before or after it, so the description and the caption are heard together. Keep the Caption tag beside the Figure tag rather than inside it, because Adobe notes that alt text on a parent tag stops a screen reader from reading that tag's children. If you use the Reading Order tool's Figure/Caption option, which tags both as one unit, check the result. For a chart, the alt text covers the chart and the labels drawn inside it, and a source line or side note set as real text follows the chart. Our guide to alt text for charts, maps and diagrams covers the description itself.

On a cover, read the title, subtitle, organization and date first, and mark a purely decorative background photo as an artifact. Text over a photo can also fail color contrast.

Footnotes and endnotes

Tag the superscript marker in the text as a Reference and the footnote itself as a Note. Where the Note goes is a judgment call. The University of Illinois Springfield's guide says there is no settled standard, and its own remediation team places notes after the paragraph that cites them. That is a good default, because the listener hears the note while the sentence is still fresh. Endnotes can stay at the end, with each marker linked to its note.

Running headers, footers and page numbers

Running headers, footers and page numbers repeat on every page, so they should be artifacts. W3C's technique PDF4 lists header and footer information, separator lines and decorative images as typical artifacts, and PDF14 describes Word exporting headers and footers as pagination artifacts. Artifact only what is repeated or decorative. A footer that says something found nowhere else, such as a "Draft, not adopted" notice on a budget book, should be read once, so tag it as text on the first page.

Reading order in tables, forms and bilingual layouts

Tables

A screen reader reads a table row by row, left to right, and can announce the matching headers as a user moves from cell to cell, but only if the table is tagged as a table. A budget table exported as loose paragraphs reads as a stream of numbers. W3C's technique PDF6 expects table rows (TR) holding header cells (TH) and data cells (TD), in the proper order. Multi-row headers need someone who knows which labels apply to which numbers. A table used only for layout should not be tagged as a data table. For depth, see the tables rule.

Forms

On a permit application or patient intake form, each label and its instructions should be read just before the field they describe, and the Tab key should reach fields in the same order. Set the tab order to Use Document Structure so it follows the tags. W3C's technique PDF10 treats a field's tooltip as its label. Our guide to accessible PDF forms covers the rest.

Side-by-side languages

Bilingual notices often set English and Spanish side by side. Read one complete language version, then the other, rather than alternating paragraph by paragraph. The exception is a bilingual form that pairs each label with its translation, where label-by-label pairs make sense. Put each version in its own container and set its language, so the screen reader switches pronunciation. That is WCAG 3.1.2 Language of Parts, and W3C's technique PDF19 shows how to set it in Acrobat's Tags panel. For scanned pages in right-to-left scripts such as Arabic or Hebrew, plan on a person checking the reading order after OCR.

Set the order once in your template

Most complex layouts come from templates that repeat, such as the monthly newsletter or the annual report. Fixing one export in Acrobat helps one file. Fixing the template helps every future issue.

• In InDesign, add page items to the Articles panel in reading order, choose Use for Tagging Order in Tagged PDF, and export with Create Tagged PDF turned on.
• In Word, keep sidebars and callouts in the main text at the point they should be read, not in floating text boxes, and use the built-in heading styles.
• Mark decorative images and rules as decorative in the source wherever your tool allows it.

How Ockem Proof handles complex layouts

Ockem Proof, our product, does the structural repair and puts the judgment calls in front of a person.

• Repairs in place. Proof rebuilds broken structure in place and keeps what is already correct, such as figures, tables, links and lists. A document with no tags goes through tagging first, so fixers never report progress they did not make.
• Checks its own work. Any automated change that does not measurably improve the document is discarded. A fix that would remove or hide text the document already had, or a structural fix that would change what is painted on the page, is refused, and the run carries on from the earlier version.
• Holds structure to a stricter bar. A list or data table tagged as plain paragraphs does not pass, and neither does a link tagged around the wrong words. Proof shows exactly where.
• Shows the order on the page. Proof compares each page's visual order with its tag order. Flagged pages get a numbered overlay that shows the exact order assistive technology will follow, block by block. To change it, you draw the order directly on the page, and Shift-drag to draw a table. Screen reader users are pointed to a keyboard method.
• Leaves content calls to people. Second-language passages are surfaced with their locations for a person to confirm, and ambiguous tables go to a table editor instead of being guessed.
• Says when it cannot finish. A document exported with no repairable structure gets a "needs re-authoring" advisory with the reason. On a document Proof couldn't finish, "Have Ockem do this" asks our experts for a price in documents, which you accept or decline in Proof.

Whether the sidebar comes before or after the story is still your decision. A person confirms the final order, and that confirmation is recorded on the certificate as your organization's attestation. The reading order rule has the details.

Next steps

You can try one PDF (opens an external site) of up to 10 pages free, with no account. To size your library first, use the free PDF inventory tool. For how each check is handled, see the reading order rule and the tables rule. Related guides: logical reading order in PDFs, which checks software can fix and accessible PDF forms.

Questions

This guide explains the rules in plain language. It isn’t legal advice. Check how they apply to your organization with counsel.