What you are seeing
This fix restores all three finder patterns to the printed code. You will inspect every corner of the proof, find what removed or damaged the missing corner, and correct the artwork, the trim, or the placement. Verify all three corners on the corrected proof before approving the run.
Likely causes
1.
Logo or graphic covering a corner — Quick test: compare the proof corners with the digital file.
2.
Trim cutting off a corner — Quick test: check the margin at the trim side on several copies.
3.
Fold, crease, or damage across a corner — Quick test: inspect the proof corners for folds or damage.
4.
Print fault in one corner — Quick test: check whether the same corner fails on every copy.
5.
Sticker or label overlapping the code — Quick test: look for any overlapping label on the finished item.
Step-by-step fix
Step 1: Inspect all three corners of the proof and mark the one that is missing or damaged.
Step 2: Compare the proof corners with the digital file to confirm what changed.
Step 3: Remove or move anything covering the corner, such as a logo, a sticker, or an overlapping label.
Step 4: If trimming cut the corner, move the code away from the trim edge and add trim allowance.
Step 5: If a fold crosses the corner, move the code away from the fold line.
Step 6: If the same corner fails on every copy, fix the printer fault, then reprint.
Step 7: Reprint one proof, confirm all three corners are complete, and scan it on two phones before approving the run.
Putting this into practice
In practice, add a three-corner check to the proof routine: top left, top right, bottom left, all complete and matching the file. A proof that fails the corner check is a proof that fails, however good the rest of it looks. Record the before-and-after behaviour with the job file, so the fix is provable rather than anecdotal. When the same failure appears again, that record tells you whether the old fix held or a new cause appeared.
Common mistakes to avoid
- Placing a logo over a corner finder pattern and discovering the code cannot be found by any scanner.
- Reprinting the full run before a single proof passes, which turns one failure into many.
- Testing on one phone in ideal conditions instead of two phones in the real conditions where a code that prints with a missing finder pattern will be used.
- Changing the artwork and the placement at the same time, so you cannot tell which change fixed a code that prints with a missing finder pattern.- Skipping the proof test because the change looked small, when small changes cause most repeat failures.
Quick checklist
- All three finder patterns are complete and match the file
- No logo, sticker, fold, or trim touches a corner
- The proof scans on two phones
- The corrected proof passes on two phones in the real conditions
- The fix is recorded in the job file so the next reprint starts from a proven setup
- Every printed copy is checked against the approved proof
- The proof is retested after any later change to the link, design, or placement
Related tools and guides
- [QR minimum size checker](/qr-minimum-size-checker)
- [QR contrast checker](/qr-contrast-checker)
- [QR print proof checklist](/qr-print-proof-checklist)
- [QR DPI calculator](/qr-dpi-calculator)
- [QR quiet zone calculator](/qr-quiet-zone-calculator)
- [printed QR tester](/printed-qr-tester)
- [QR size calculator](/qr-size-calculator)
