Make PDF page numbers match the printed pages
The page number a PDF viewer announces should match the number printed on the page. PDFs handle this with page labels, set through the PageLabels entry in the document catalog, so front matter can run i to iv and the body can start again at 1 exactly as printed. Appendices work the same way, starting at 1 with a letter prefix, so page A-1 announces as A-1. W3C publishes PDF17 as a sufficient technique. Without page labels the viewer just counts physical sheets, the navigation toolbar shows that count, and page 12 of the file is page 8 of the document.
How we find it in an audit
We compare the viewer's page indicator against the numbers printed on the pages, and we do it once per numbering scheme rather than once per document, because front matter, body and appendices each need their own. In Acrobat we check whether page labels are defined and agree with the print throughout.
How affected users experience it
"See page 47 of the agreement" is a normal instruction in legal work. With no page labels, a screen reader user navigating to page 47 lands on printed page 43, and every citation, index entry, and phone-call reference is off by the same silent offset. They have no visual page corner to double-check against.
Passes vs. fails
Passes
Page labels number the front matter i to vi and start the body at 1. The viewer's page 31 is the printed page 31, for everyone.
Fails
A prospectus has six pages of roman-numeraled front matter and no page labels. Counsel says "see page 31", and the viewer's page 31 is printed page 25.
How this gets tested
The W3C publishes test rules that define what a checker looks for here.
- ARIA attribute is defined in WAI-ARIAA tool can check this
- ARIA state or property has valid valueA tool can check this
- Element with role attribute has required states and propertiesA tool can check this
- Form field has non-empty accessible nameA tool can check this
- Headers attribute specified on a cell refers to cells in the same table elementA tool can check this
- Role attribute has valid valueA tool can check this
- ARIA global properties not used where prohibitedA tool can check this
- ARIA required context roleA tool can check this
- ARIA required owned elementsA tool can check this
- ARIA state or property is permittedA tool can check this
- Table header cell has assigned cellsA tool can check this
Other ways to satisfy this rule
52 guides on this site are filed under 1.3.1 Info and Relationships. W3C lists this one as sufficient for that rule when used for making information and relationships conveyed through presentation programmatically determinable, so the condition is part of the test rather than a footnote to it.
- ARIA11sufficientAdd landmarks so users can skip around
- ARIA12sufficientUse role=heading when h1-h6 is impossible
- ARIA13sufficientName repeated landmarks so they are distinguishable
- ARIA16sufficientName controls from visible text with aria-labelledby
- ARIA17sufficientGroup related form fields with ARIA roles
- ARIA20sufficientMark leftover page areas with role=region
This guide is our interpretation of W3C technique PDF17: Specifying consistent page numbering for PDF documents. W3C publishes its techniques as guidance rather than as the standard, and says so on every one of them. The success criterion is what conformance is measured against, and a technique is one documented way to meet it.