Matterhorn 01-001 · PDF/UA-1 UA1:7.1-1
Decoration tagged as content: rules, borders, flourishes
Decoration — a rule line, a page-border image, a watermark, a background flourish — has been given a real content tag, so assistive technology announces it as if it were part of the document.
The condition, as the protocol states it. “Artifact is tagged as real content.”
Matterhorn Protocol 1.1, checkpoint 01, index 01-001, section UA1:7.1-1. The protocol marks this as requiring human judgement.
What a screen reader actually does
The screen reader announces meaningless content: "graphic", a stray blank paragraph, or a run of decorative characters, interrupting the flow of the actual text.
What the condition is
PDF/UA divides everything a page paints into two kinds. Real content is inside a marked-content sequence that a structure element claims, and it is read. An artifact is inside an /Artifact sequence, belongs to no element, and is not read. Condition 01-001 is the first kind holding something that should have been the second.
Here is a rule line drawn with characters, tagged as a paragraph:
/P <</MCID 7>> BDC
BT /F1 11 Tf 1 0 0 1 72 410 Tm (----------------) Tj ET
EMC31 0 obj
<< /Type /StructElem /S /P /P 9 0 R /Pg 3 0 R /K [ 7 ] >>
endobjand the same line as decoration, which no structure element points at:
/Artifact <</Type /Layout>> BDC
BT /F1 11 Tf 1 0 0 1 72 410 Tm (----------------) Tj ET
EMCISO 32000-1 gives artifacts a type — Pagination for running heads, page numbers and watermarks, Layout for rules and ornaments, Page for production marks such as cut marks, Background for full-page washes. The type matters for running heads and footers (18-002). For decoration, what matters is that it is outside the tree.
The usual suspects: horizontal rules, page borders, corner ornaments, background images, a coloured band behind a heading, a logo repeated as wallpaper, and lines made of dashes, underscores or box-drawing characters.
What the user hears
The decoration, as if it were part of the text. A border image tagged as a Figure is announced as a graphic — with no description, because nobody writes alt text for a line. A rule drawn with characters is read out as characters or passed over silently, depending on the reader’s punctuation setting — and either way the reader stops on it, because the file says it is a paragraph.
One instance is a stumble. A document that tags every ornament makes the listener sit through them on every page, and teaches them to skip ahead — past the content as well.
Where it comes from
Auto-tagging. Adobe says it plainly in its Reading Order tool documentation: Acrobat cannot always tell instructive figures from decorative page elements, and may tag decoration as figures. Every geometric tagger has the same problem, because a border and a diagram are both pictures.
Rules made of text. A line of underscores or ─ characters typed as its own paragraph is a paragraph to the authoring application, and exports as one.
Hand tagging. Dragging a Reading Order region over a block of text that also covers the rule beneath it puts both in one tag.
How to check it free
In Acrobat Pro, open the Tags panel and turn on Highlight Content from its Options menu. Walk the tree; any element whose highlight lands on a line, a border or a background is this condition.
The Reading Order tool is faster for images: All tools → Prepare for accessibility, then Reading Order (Adobe’s pages also call it Fix reading order), then Show Tables And Figures. Adobe describes it as outlining each figure with a crossed-out box that also shows whether the figure has alternate text. Decorative figures stand out, because they are the ones nobody described.
The Accessibility Checker catches the image case indirectly. Its Figures alternate text rule asks that images “either have alternate text or are marked as artifacts” (Adobe), so an undescribed decorative figure fails it — and the right response is to artifact the image, not to describe a border. Nothing in the checker’s rule list looks at text-character rules.
How to fix it free, in Acrobat Pro
From Adobe’s Content and Tags panel documentation:
From the Tags panel. Select the element, then Options → Change Tag To Artifact. Adobe’s description: it “changes selected tags to artifacts and removes the tagged content from the structure tree” — the content is re-marked, not just orphaned.
From the page. Open the Reading Order tool, select Show Page Content Groups, Page Content Order and Show Tables And Figures, select the element in the document pane, and click Background/Artifact.
From the Content panel, for objects the tree does not reach: right-click the object → Create Artifact.
Not Delete Tag: that takes the element out of the tree without making its content an artifact, so the content is left neither tagged nor an artifact — which swaps this warning for a 01-005 failure.
Upstream is better where the decoration is an object. InDesign’s Tags panel (Window → Utilities → Tags) has an Artifact tag you can apply to a selected frame (Adobe). A rule typed as characters is best replaced at source with a paragraph border, which is drawn rather than written.
Where Taggart differs
Taggart’s check is a narrow heuristic, and worth knowing exactly. It looks at <P>, <Span>, <Div> and <Figure> elements whose text — what they paint on the page, or their /ActualText or /Alt when they paint none — is at least three characters long and made of nothing but rule characters: hyphens, en and em dashes, underscores, box-drawing lines, dots, bullets, asterisks, equals signs, tildes and spaces:
<P>contains only rule/decoration characters (’--------------------’) but is tagged as real content.
A row of dashes painted in an ordinary <P> is reported. A border image tagged as a figure is not: if it has no alt text it arrives as 13-004 instead, whose message says a decorative image should be an artifact; if somebody described it, nothing is reported at all. Treat a clean result for 01-001 as “nothing obvious”, not as a review.
The finding is a warning, so it goes to the review queue, where you record whether the element really is decoration. Recording it changes nothing in the file.
The engine also has a repair, artifact-decorative, that will run only on element paths a reviewer has approved; without them it refuses:
each decorative element must be approved by a reviewer; artifacting content removes it from the reading order entirely
With approval, it takes the element out of the structure tree — and stops there. The content stream is not rewritten, so the characters are still marked as content, now belonging to no element, and the re-check reports them as 01-005:
Page 1 paints 1 object(s) in 1 marked-content sequence(s) that no structure element can be found for through the parent tree, so assistive technology cannot tell what they are — 1 of them belong to no element at all.
That is the same result as Acrobat’s Delete Tag, and the wrong one. Until the repair re-marks the content as an artifact, make the change in Acrobat with Change Tag To Artifact.
How Taggart handles it
The protocol marks this condition as needing human judgement, so no validator can decide it outright. Taggart applies a heuristic to find the likely cases and reports each one as warning for you to settle in the review queue. A heuristic finds what it was built to find and can miss the rest; what this one looks for is described above.
The fix is Mark decorative content as an artifact. It changes what the document means, so Taggart proposes it and waits for your approval rather than applying it unattended.
Whatever Taggart changes, the page still looks identical. Fixes edit the PDF object model, not the content streams, and every remediation is re-rendered and compared against the original at structural similarity ≥ 0.999 before you get the file back. A tool that quietly reflows your document is worse than no tool.
Frequently asked questions
Is an empty Alt enough to mark an image as decorative?
No. In HTML alt="" means decorative; in PDF there is no such convention. A Figure with an empty /Alt is still a Figure, still in the reading order, and still announced as a graphic. Decoration has to be an artifact, which takes it out of the structure tree altogether.
Can I just delete the tag?
Deleting the element removes it from the tree but leaves the content marked as it was, so it ends up neither tagged nor an artifact — condition 01-005, which is a failure every checker reports. Use an artifact command, which says what the thing is.
Why is this a warning and not a failure?
Because whether something is decoration is a judgement about the document. A row of underscores is a rule in a letterhead and a blank to write on in a form. The Matterhorn Protocol marks the condition as needing a person, and no validator can decide it.
Does Taggart make the decoration an artifact for me?
Not yet in a way you can rely on. Its repair removes an approved element from the tree but leaves the content stream as it was, so the re-check reports the same characters as 01-005. Use Acrobat's Change Tag To Artifact for now.
Where this sits in the standards
| Standard | Reference |
|---|---|
| Matterhorn Protocol 1.1 | Checkpoint 01 (Real content tagged), index 01-001 |
| PDF/UA-1 (ISO 14289-1) | Clause 7.1-1 |
| WCAG 2.1 | 1.3.1 Info and Relationships — Level A |
| EN 301 549 / Section 508 / ADA Title II | All three point at WCAG 2.1 Level AA for non-web documents, so a Level A or AA criterion here is in scope for each of them. |
Related conditions
- 01-002 Real content marked as artifactContent that carries meaning has been marked as an artifact, which removes it from the structure tree entirely. This is the most damaging single mistake in PDF remediation because the content becomes invisible rather than merely mis-labelled.
- 01-005 Content is neither marked as Artifact nor tagged as real contentEvery text-showing, image-painting and path-painting operator on a page must sit either inside a marked-content sequence that maps to the structure tree, or inside an artifact sequence. Content that is in neither is orphaned.
- 13-004 Figure tag alternative or replacement text missingA Figure element has neither /Alt nor /ActualText. Every Figure must have one or the other; if the image is decorative it should be an artifact instead of a Figure.
- 18-001 Headers and footers are not marked as pagination artifactsRunning heads, footers and page numbers are tagged as real content, so they repeat in the reading order on every page.
Other conditions in checkpoint 01
Checkpoint 01 covers real content tagged. These are its other failure conditions; the ones without a link are in the rule set but do not have a written page yet.
- 01-002 Real content marked as artifactContent that carries meaning has been marked as an artifact, which removes it from the structure tree entirely. This is the most damaging single mistake in PDF remediation because the content becomes invisible rather than merely mis-labelled.
- 01-003 Content marked as Artifact is present inside tagged contentA BMC/BDC artifact sequence has been opened while a marked-content sequence for real content is still open. Artifacts and real content may not be nested inside one another.
- 01-004 Tagged content is present inside content marked as ArtifactA marked-content sequence for real content has been opened inside an open artifact sequence. The artifact swallows the real content.
- 01-005 Content is neither marked as Artifact nor tagged as real contentEvery text-showing, image-painting and path-painting operator on a page must sit either inside a marked-content sequence that maps to the structure tree, or inside an artifact sequence. Content that is in neither is orphaned.
- 01-006 Structure type is not semantically appropriateThe tag does not match the nature of the content: a heading tagged as a paragraph, a data table tagged as a layout container, a caption tagged as body text. This is the judgment call that no validator can make for you.
- 01-007 Suspects entry has a value of trueThe MarkInfo dictionary carries /Suspects true, which is the producing application's own declaration that its tagging may be unreliable. PDF/UA-1 requires the value to be false.
Check your own file. Taggart’s validator is free and unlimited — 75 of the 87 Matterhorn conditions software can decide, with the other 12 listed for you to confirm; no watermark, no expiry, and no account needed up to 60 pages.
Checked with Taggart on a generated file that fails this condition on . The Acrobat steps follow Adobe’s documentation and were not walked through by hand. Last updated .