What this error means
Crop marks are short corner lines printed outside the trim area to show a press operator where to cut. KDP's printers are fully automated and use the PDF's internal trim box to slice pages — they don't need (or want) crop marks. KDP's spec explicitly states "no crop marks, annotations, bookmarks, or comments in PDF."
If the checker detects printer marks, the rejection reads "Your PDF contains printer marks that must be removed." The same rule covers registration marks (used to align colour plates), colour bars (calibration stripes), page information labels, and slug area marks.
This affects covers far more than interiors — designers experienced with commercial print add crop marks by reflex, since they're required by every UK litho printer outside KDP.
Why it happens
Designer reflex. A cover designer who works mostly with Lulu, Ingram Spark, or local UK printers adds crop marks automatically. They forget that KDP is different.
InDesign's "PDF/X-1a" preset adds marks by default. Under Marks and Bleeds, "All Printer's Marks" is often left ticked from a previous job.
Illustrator export. When saving as PDF for print, Illustrator's "Marks and Bleed" tab defaults to having crop marks on.
Canva Pro has a "Crop marks and bleed" checkbox — toggling it on adds both. If you need bleed but not crop marks, Canva can't do both selectively. You have to add bleed in design dimensions and untick the checkbox.
Acrobat / Preview "Print to PDF" sometimes adds page labels and printer marks depending on print preset settings.
Templates from print-on-demand competitors (Ingram, Lulu) ship with crop marks baked in. Re-using those templates without modification fails KDP.
The fix
Step 1: Identify whether your file has printer marks. Open in Acrobat → Print Production → Add Printer Marks → if the dialogue's "Crop Marks" is already ticked, your file has them. Cancel without changes.
Step 2 (InDesign): File → Export → PDF → Marks and Bleeds tab → uncheck all printer marks (Crop, Bleed, Registration, Colour Bars, Page Information). Leave "Use Document Bleed Settings" ticked so bleed is preserved without marks. Export.
Step 3 (Illustrator): File → Save As → Adobe PDF → Marks and Bleeds → uncheck "All Printer's Marks". Save.
Step 4 (Affinity Designer / Publisher): File → Export → PDF → Marks → uncheck Crop Marks, Bleed Marks, Registration Marks. Keep "Include bleed" ticked. Export.
Step 5 (Canva Pro): Download → PDF Print → uncheck "Crop marks and bleed". This removes both. If you need bleed, you must have built it into the document size from the start (e.g. 6.125 × 9.25 for a 6×9 with bleed) rather than relying on Canva to add it at export.
Step 6 (Acrobat post-fix): If you can't easily re-export, open the PDF → Print Production → Add Printer Marks → cancel → then Tools → Edit PDF → delete the corner mark objects by hand. This is fiddly but works. Alternatively, Print Production → Set Page Boxes → uncheck "Show all boxes" and crop to the trim box only. Save As.
Step 7: Verify. Open the new PDF in Acrobat → View at 100% → zoom to each corner. There should be no small black lines just outside the page corners. Then Print Production → Output Preview → no "Trim Marks" listed.
Step 8: If you needed bleed, confirm it's still present — the PDF page size should equal trim + bleed (e.g. 6.125 × 9.25" for a 6×9 with bleed), not trim only.
How to pre-flight it
Our free KDP Readiness Score detects crop marks, registration marks, and other printer marks by parsing the PDF's content stream. Plus 30+ other KDP rules. Run it before submission and you'll catch the marks while still in your design tool.
Related errors
- KDP error: bleed misconfigured
- KDP error: cover dimensions don't match interior
- KDP error: transparency not flattened
FAQ
Why does Lulu accept crop marks but KDP doesn't? Different print workflows. Lulu's press uses traditional sheet-fed offset where crop marks help. KDP uses POD (print-on-demand) digital presses that trim automatically from PDF metadata.
Does the "trim box" do the same job as crop marks? Yes — modern PDFs include a TrimBox that tells the printer exactly where to cut. KDP uses this. Crop marks are visual redundancy that the press doesn't need.
Can I leave registration marks but remove crop marks? No — KDP rejects all printer marks. Remove every type.
My cover from a freelance designer has crop marks — do I send it back? You can either send it back asking for a clean export, or remove the marks yourself in Acrobat (steps above). The fix takes about five minutes if you know where the controls are.
