Matterhorn 28-017 · PDF/UA-1 UA1:7.18.8-1
Printer's marks tagged as content in the PDF structure tree
Crop marks and registration targets are production artefacts and must not appear in the structure tree.
The condition, as the protocol states it. “A PrinterMark annotation is included in the logical structure.”
Matterhorn Protocol 1.1, checkpoint 28, index 28-017, section UA1:7.18.8-1. Software can decide this one on its own.
What a screen reader actually does
Printer marks are announced as document content.
What a printer’s mark is
A PrinterMark annotation is the PDF object for the furniture a press needs: crop and cut marks, registration targets, colour bars. It is drawn by its own appearance stream, sits on the page like any other annotation, and its optional /MN entry names the kind of mark:
31 0 obj
<< /Type /Annot /Subtype /PrinterMark
/MN /RegistrationTarget
/Rect [ 10 10 30 30 ]
/AP << /N 32 0 R >> % the drawing; 28-018 is about this
>>
endobjPDF/UA-1 clause 7.18.8 treats these as incidental artifacts — as if they were hidden page elements. They are not content, so they have no place in the structure tree. This condition fires when one is there anyway:
/Document
├── /P "Quarterly report, print edition…"
└── /Annot
└── OBJR → 31 0 R % a registration target, in the reading orderWhat it costs a reader
The <Annot> element is a stop in the reading order with nothing behind it that means anything. A user moving element by element reaches it and gets an annotation — announced by whatever their screen reader says for one — attached to a target printed outside the trim. On a print-ready file with marks at every corner of every page, the stops multiply with the page count, and they come wherever the tagger happened to put them in the tree.
It is not misleading. It is noise in the one channel a non-visual reader has, and the content it interrupts is real.
Where it comes from
Tagging passes that wrap every annotation. The safe rule for most annotations is “put it in an <Annot>”, and a tagger that applies it without looking at the subtype tags printer’s marks along with the comments.
Answering Acrobat’s checker. Adobe documents the Accessibility Checker’s Tagged annotations rule as checking whether all annotations are tagged, and asks that they be either in the Tags tree or marked as artifacts (Adobe: Create and verify PDF accessibility). The page does not say whether printer’s marks are excepted. A remediator who answers a failure there by tagging the mark has produced this condition.
Taggart’s own bulk repair, in one situation, described at the end of this page.
Adobe documents Acrobat’s own way of embedding marks — All tools → Use print production → Add printer marks, permanently and optionally in a layer (Adobe: Printer marks and hairlines) — but not whether it writes them as PrinterMark annotations or as page content. Look in the file rather than assuming.
How to check it free
veraPDF reports it against clause 7.18.8: “A PrinterMark annotation is included in logical structure”. Its test exempts marks that are hidden or outside the crop box.
Acrobat Pro’s Tags panel shows it, if you know where to look. Open it from the hamburger menu (Windows) or the View menu (macOS) → Show/Hide → Side Panels → Tags, turn on Highlight Content from the panel’s Options menu — Adobe documents it as outlining, on the page, the content related to the tag you select — and select each <Annot> element. One that outlines a crop mark or a colour bar is the condition. Turning on Show Art, Trim, & Bleed Boxes in the Page Display preferences (Adobe: Viewing preferences) makes it easier to see which marks sit outside the trim.
How to fix it free, in Acrobat Pro
The repair is to remove the element, not the mark. Adobe documents the Tags panel’s options (Adobe: Edit document structure with the Content and Tags panels):
- In the Tags panel, select the
<Annot>whose highlight is the printer’s mark. - Right-click it, or open the Options menu, and choose Delete Tag.
- Save, and check again.
The mark still prints; it is simply no longer something a reader walks through. Do not tag it as anything else in its place — the condition is that it is in the tree at all.
If the file is going to be read on screen rather than sent to press, consider whether it needs printer’s marks at all. A version exported without them avoids this condition and 28-018 together.
What Taggart does
The check finds every PrinterMark annotation that a structure element references, and names the element:
A PrinterMark annotation on page 1 is referenced from the structure tree (<Annot>). Printer marks are production artefacts and must not appear in logical structure.
The repair is printermark-artifact, and it is in Fix All Safe. It removes the object reference from the element’s kids and logs it — page 1: removed the PrinterMark annotation from <Annot> in the structure tree. The annotation, its appearance and the printed result are untouched.
Its limits, and one thing that undoes it:
- It reads a kids array. Where the element’s
/Kis the object reference itself rather than an array holding it, the repair reports nothing to do and the finding stays. Delete the tag in Acrobat as above. - It does not touch the appearance stream. Whether the mark’s drawing is marked as an artifact is 28-018, and this repair does not clear it.
- It is stricter than veraPDF. Taggart reports hidden marks and marks outside the crop box, which veraPDF’s test exempts.
- Fix All Safe can put it back. The repair for 28-002, also safe, wraps every untagged annotation that is not hidden or a Popup — a printer’s mark included — and runs after this one. In a document that also has an untagged comment, the output of one bulk pass has the mark back in an
<Annot>and 28-017 reported against it; a mark that was never in the tree can be put there the same way. Run Fix All Safe a second time: there is nothing left for the 28-002 repair to do, so this repair runs on its own and the finding clears.
How Taggart handles it
Taggart checks for this condition automatically and reports it as a blocker, with where in the file it found it.
The fix is Artifact printer marks. It is mechanical, so “Fix All Safe” applies it along with the others in one pass and lists what it changed. Your original file is never modified.
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
Every other annotation has to be tagged. Why not this one?
Because it is not part of the document. PDF/UA-1 clause 7.18.8 treats PrinterMark annotations as incidental artifacts, as if they were hidden page elements: they exist for the people running the press, the way crop marks on a proof do. The rule that puts annotations in an Annot structure element (28-002) exempts them for the same reason.
Will removing the tag remove the marks from the print?
No. The tag is in the structure tree; the mark is an annotation on the page with its own appearance. Deleting the tag changes what a reader encounters and nothing that prints.
Taggart's Fix All Safe cleared it, then reported it again. Why?
Because a second safe repair put it back. When the document has another annotation that is not yet tagged, the repair for 28-002 wraps every untagged annotation it finds — the printer's mark included — and runs after the printer-mark repair. Run Fix All Safe a second time: with nothing left for the 28-002 repair to do, the printer-mark repair runs alone and the finding clears.
Does veraPDF agree with Taggart on this one?
On ordinary files, yes. veraPDF's test exempts a PrinterMark annotation that is hidden or lies outside the crop box; Taggart reports those too. A print-ready file whose marks all sit outside the crop box can pass veraPDF and still be reported by Taggart.
Where this sits in the standards
| Standard | Reference |
|---|---|
| Matterhorn Protocol 1.1 | Checkpoint 28 (Annotations), index 28-017 |
| PDF/UA-1 (ISO 14289-1) | Clause 7.18.8-1 |
| 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
- 28-018 The appearance stream of a PrinterMark annotation is not marked as ArtifactThe content inside a PrinterMark's appearance stream must itself be artifacted.
- 28-002 An annotation is not a direct child of an Annot structure elementNon-widget, non-link annotations must sit inside an Annot structure element so they have a place in the reading order.
- 01-001 Artifact tagged as real contentDecoration — 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.
- 28-007 An annotation of subtype TrapNet existsTrapNet annotations are prepress artefacts and are forbidden in PDF/UA-1.
Other conditions in checkpoint 28
Checkpoint 28 covers annotations. These are its other failure conditions; the ones without a link are in the rule set but do not have a written page yet.
- 28-001 An annotation is not in correct reading orderThe annotation's position in the structure tree does not match where it appears on the page.
- 28-002 An annotation is not a direct child of an Annot structure elementNon-widget, non-link annotations must sit inside an Annot structure element so they have a place in the reading order.
- 28-003 An annotation is used for visual formatting but is not tagged according to its semantic functionA Square or Line annotation used to draw a box round a callout is decoration and should be artifacted, or tagged for what it actually means.
- 28-004 An annotation has neither a Contents entry nor an alternative descriptionEvery non-widget annotation needs an accessible description, either in its own /Contents or in the /Alt of the structure element that encloses it.
- 28-005 A form field has neither a TU entry nor an alternative descriptionThe /TU tooltip is the accessible name of a PDF form field. Without it the field has no name at all — the visible label printed next to it is not connected to the control.
- 28-006 An annotation with subtype undefined in ISO 32000 does not meet 7.18.1A custom annotation subtype still has to be placed in the structure tree and described.
- 28-007 An annotation of subtype TrapNet existsTrapNet annotations are prepress artefacts and are forbidden in PDF/UA-1.
- 28-008 A page containing an annotation does not contain a Tabs entryAny page carrying annotations must declare a tab order. PDF/UA-1 requires /Tabs /S — tab order follows the structure tree.
- 28-009 A page containing an annotation has a Tabs entry with a value other than S/Tabs is present but set to /R (row order) or /C (column order) rather than /S (structure order).
- 28-010 A widget annotation is not nested within a Form tagEvery form control must sit inside a Form structure element.
- 28-011 A link annotation is not nested within a Link tagA link annotation must be a child of a Link structure element containing the link's text, joined by an object reference (/OBJR).
- 28-012 A link annotation does not include an alternate description in its Contents entryLink annotations need /Contents describing where the link goes.
- 28-013 An IsMap entry is true but the functionality is not provided in some other wayA server-side image map requires pointing at a pixel, which is not possible without a mouse.
- 28-014 CT entry is missing from the media clip data dictionaryThe media clip's content type (/CT) is required so a processor knows what it is being asked to play.
- 28-015 Alt entry is missing from the media clip data dictionaryMedia clips require an /Alt array giving a text description.
- 28-016 File attachment annotations do not conform to 7.11The file specification referenced by a FileAttachment annotation must carry both /F and /UF.
- 28-018 The appearance stream of a PrinterMark annotation is not marked as ArtifactThe content inside a PrinterMark's appearance stream must itself be artifacted.
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 .