Matterhorn 14-005 · PDF/UA-1 UA1:7.4.3-1

Seventh-level headings: when a document needs H7 and beyond

Documents deeper than six levels must use Hn tags (H7, H8 …), role-mapped because ISO 32000-1 defines only H1–H6.

What a screen reader actually does

Deep sections are flattened to level 6, so the outline misrepresents the hierarchy.

What the standard allows, and requires

ISO 32000-1 defines six numbered heading types, H1 to H6. PDF/UA-1 clause 7.4.3 lets a document that needs more levels define H7, H8 and upwards, without limit, on two conditions: the new tags follow the same sequencing rules as the first six (begin at H1, never skip a level on the way down), and they are named as H plus Arabic numerals (14-004).

They are still not standard types. PDF/UA-1 requires every non-standard type to be role-mapped to the nearest functionally equivalent standard one, so an H7 needs a role map entry, and the natural target is H6:

/StructTreeRoot
   /RoleMap << /H7 /H6  /H8 /H6 >>
   …
/H6   "4.2.1.3.2.1  Notice periods"
/H7   "4.2.1.3.2.1.1  Notice by email"     ← tag keeps the seventh level

Condition 14-005 is the opposite case: content that is a seventh-level heading, tagged as something else — typically H6, or P.

What is lost

/H6   "4.2.1.3.2.1  Notice periods"
/H6   "4.2.1.3.2.1.1  Notice by email"     ← flattened
/P    "Notice given by email takes effect…"

Read as a tree, this says Notice by email is a peer of Notice periods — another sixth-level section — rather than part of it. A screen-reader user moving by heading level, or reading the headings list, sees two siblings where the document has a parent and a child, and the clause numbering in the text contradicts the structure that is supposed to carry it.

The honest limit of the fix is worth knowing too: with H7 → H6, a reader that follows the role map still announces heading level 6. What the H7 tag buys is that the seventh level exists in the file at all. Nothing downstream can recover a level that was never written.

Where it comes from

Authoring tools that offer more heading levels than PDF has: Word has nine built-in heading styles. What a given version writes to a tagged PDF for Heading 7 to 9 is worth checking in the Tags panel rather than assuming. Generators that stop at six and clamp anything deeper to H6. And remediation in Acrobat, whose Reading Order tool offers Heading 1 to Heading 6 — Adobe’s description of the heading elements says six levels are available — so a seventh level gets the nearest of those.

How to check it

This is a judgement because only the document can say how deep its headings go.

1. Establish the real depth. Clause numbering is the easy case: a heading numbered with seven parts is level seven. Otherwise, work from the document’s own outline or contents page.
2. Compare it with the tags. In Acrobat Pro’s Tags panel (View → Show/Hide → Side Panels → Tags), find the deepest headings. Any heading deeper than the H6 above it but tagged H6 or P fails.
3. Check the role map. Options → Edit Role Map in the Tags panel shows whether H7 and any deeper types are mapped. (Adobe: Edit document structure with the Content and Tags panels)

veraPDF’s PDF/UA-1 rule 7.1-5 catches an H7 with no role map entry. It has no rule for clause 7.4.3, so a flattened document passes it. (veraPDF PDF/UA-1 rules)

How to fix it free, in Acrobat Pro

From Adobe’s Tags panel documentation, whose dialogs let a tag type be typed rather than picked from the menu:

1. Select the heading’s text on the page. In the Tags panel, choose Create Tag From Selection from the Options menu and give H7 as the type.
2. If the element the text came from is left empty, remove it with Delete Tag.
3. Repeat for each seventh-level heading, using H8 and so on for deeper ones.
4. Options → Edit Role Map, and map H7 (and each deeper type you used) to H6.

If the source has the levels — Word’s Heading 7, a numbered clause style — fixing the export is better, because the next revision will flatten them again otherwise.

What Taggart does

Taggart has no check for 14-005. 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 report is the role-mapping half. An H7 with no role map entry is 02-001:

The structure type /H7 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 maps H7 — and any deeper Hn — to /H6. The tag stays H7, so the depth survives in the file, and the heading-sequence checks (14-002, 14-003) pass on the result.

What Taggart cannot see is the failure this condition is actually about. A seventh level tagged H6 passes every heading check it runs, and so does an H7 that the role map sends to P. Both need the reading described above.

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

• 14-004 Numbered heading tags do not use Arabic numeralsCustom heading tags like "Heading-One" or "HI" must role-map to H1–H6 or to Hn using Arabic numerals.
• 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.
• 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.
• 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.

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.
• 14-004 Numbered heading tags do not use Arabic numeralsCustom heading tags like "Heading-One" or "HI" must role-map to H1–H6 or to Hn using Arabic numerals.
• 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.