Matterhorn 14-004 · PDF/UA-1 UA1:7.4.3-1

Heading tags must give their level in Arabic numerals

Custom heading tags like "Heading-One" or "HI" must role-map to H1–H6 or to Hn using Arabic numerals.

What a screen reader actually does

The heading level cannot be determined, so the element is announced without a level.

What the rule says

In the numbered heading model the level is in the tag name: H1 to H6 are defined in ISO 32000-1, and PDF/UA-1 clause 7.4.3 lets a document that needs more go on to H7, H8 and beyond. The same clause fixes how those names are written: the letter H followed by Arabic numerals, with no whitespace, no separators and no other numbering system. Its notes give Roman numerals as the example of what is not allowed, and H1,247 and H1 247 as names that fail where H1247 passes.

The Matterhorn Protocol turns this into condition 14-004 and widens it slightly: a numbered heading tag that does not use Arabic numerals fails unless it is role-mapped to a heading type that does. So the tag name is allowed to be anything, provided the role map resolves it to Hn.

What the reader gets

A reader follows the role map. HII → H2 is announced as heading level 2 and appears in the headings list at the right depth; the tag’s name never reaches the listener.

Without a usable mapping the reader has nothing to announce. A type with no role map entry is not a type it knows, so the text is read and the heading is not a heading. A type mapped to P is a paragraph to the reader, and missing from the headings list. Either way the user who navigates by heading loses this one, and every heading under it appears to belong to the one before.

Where it comes from

Producers that name tags after the author’s paragraph styles, when a style is called something like Heading Two or Titre II. Converters from structured XML, where heading elements are named by the source schema. And hand edits in Acrobat: the New Tag dialog accepts a typed tag type as well as one picked from the menu, so a typed HII goes into the file exactly as typed.

How to check it

This is a judgement because the question is whether an element is a heading, and at what level — the tag name only tells you what somebody called it.

1. List the custom types. In Acrobat Pro, open the Tags panel (View → Show/Hide → Side Panels → Tags) and choose Edit Role Map from its Options menu to see every role map entry the document has. A custom type with no entry is only visible in the tree itself. (Adobe: Edit document structure with the Content and Tags panels)
2. Find the ones that are headings. Any type whose name suggests a heading, and any type used on text that looks like one. Turn on Highlight Content in the Tags panel to see what each element covers.
3. Follow each to the end of its chain. It passes if it ends at H1–H6 (or at an Hn that is itself mapped, see 14-005) at the level the document’s outline needs.

veraPDF’s PDF/UA-1 profile helps with part of it: rule 7.1-5 reports a non-standard type that does not map to a standard one, which catches HII with no entry. It has no rule for clause 7.4.3, so HII → P passes it. (veraPDF PDF/UA-1 rules)

How to fix it free, in Acrobat Pro

Two routes, both from Adobe’s Tags panel documentation.

Fix the role map — best when one custom type is used for many headings at the same level:

1. Tags panel → Options → Edit Role Map.
2. Map the custom type to the numbered heading it represents: HII to H2.

Change the element type — best for a handful of elements:

1. Select the element in the Tags panel.
2. Options → Properties, choose the heading level from the Type menu, and close the dialog.

If the document came out of an authoring tool, fix the style-to-tag mapping there and re-export, or the next revision will bring the same names back.

What Taggart does

Taggart has no check for 14-004. It produces no finding of that number, so the condition never reaches the review queue. It is on the list of conditions Taggart asks a person to confirm before it will write the PDF/UA claim into the file. In the application the conformance card lists them, with one box to tick — I have checked these conditions by hand, or with another validator. Until someone has, the claim is not written. The confirmation covers the whole list at once, so make the check above before you give it.

What it does catch is the half of the problem that overlaps with role mapping. A custom type with no role map entry is reported as 02-001:

The structure type /HII is used 1 time(s) but is neither a standard type nor present in the role map.

The repair for that, rolemap-repair, runs with the safe fixes and chooses a target from the name alone:

• H followed only by digits, or “Heading” directly followed by a digit, gives that level, capped at the deepest standard one: Heading2 → H2, H8 → H6;
• any other name with “head” or “title” in it gives H1: Heading-Two becomes H1, and so does Heading_2, whose underscore keeps the digit from being read;
• anything else gives P: HI, HII and H-2 all become paragraphs.

Every mapping is written to the change log — mapped /HII to the standard type /P — and that line is the one to look for. After the repair the file passes 02-001, and a Roman-numeral heading is now a paragraph that nothing reports: one demoted heading is not enough to trip Taggart’s visual heading heuristic (14-001), which only reports when many more lines look like headings than are tagged as them. Correct the mapping by hand, as above.

A custom type whose role map entry already ends at a standard type is not reported at all, whatever that type is.

How Taggart handles it

No software can decide this one, and Taggart has no check for it, so it never appears among the findings or in the review queue. It is on the list of conditions Taggart asks you to confirm by hand before it writes the PDF/UA claim into the file — the claim waits until you have.

Where this sits in the standards

Related conditions

• 14-005 Content representing a 7th level (or higher) heading does not use an H7 (or higher) tagDocuments deeper than six levels must use Hn tags (H7, H8 …), role-mapped because ISO 32000-1 defines only H1–H6.
• 02-001 Non-standard tag mapping does not terminate with a standard typeA custom tag name is present in the role map but the chain of mappings never arrives at a structure type defined in ISO 32000-1, 14.8.4. Mapping may be indirect — a custom type may map to another custom type — but it must eventually terminate.
• 02-002 Role mapping is semantically inappropriateThe role map terminates at a standard type, but the wrong one — a custom "Sidebar" mapped to Table, or "PullQuote" mapped to Figure.
• 14-003 Numbered heading levels in descending sequence are skippedThe heading hierarchy jumps a level going down — H1 straight to H3. Going back up any number of levels is fine; going down must be one level at a time.

Other conditions in checkpoint 14

Checkpoint 14 covers headings. These are its other failure conditions; the ones without a link are in the rule set but do not have a written page yet.

• 14-001 Headings are not taggedText that is visually a heading — larger, bolder, isolated — is tagged as a paragraph. The document has no navigable outline.
• 14-002 First heading tag is not H1The document uses numbered headings (H1–H6) but the first one encountered in the structure tree is not an H1.
• 14-003 Numbered heading levels in descending sequence are skippedThe heading hierarchy jumps a level going down — H1 straight to H3. Going back up any number of levels is fine; going down must be one level at a time.
• 14-005 Content representing a 7th level (or higher) heading does not use an H7 (or higher) tagDocuments deeper than six levels must use Hn tags (H7, H8 …), role-mapped because ISO 32000-1 defines only H1–H6.
• 14-006 A node contains more than one H tagIn the strong-structure model, an unnumbered H derives its level from nesting depth, so a single structural node may contain at most one H.
• 14-007 Document uses both H and H# tagsA document must commit to one heading model: strong structure (H, levelled by nesting) or weak structure (H1–H6). Mixing them makes the level of any given heading ambiguous.

This condition needs a person’s judgement, so there was nothing for a tool to check. Written from ISO 14289-1 and the Matterhorn Protocol on 2026-10-02. The Acrobat steps follow Adobe’s documentation and were not walked through by hand. Last updated 2026-10-10.