What you are seeing
The printed code is stretched in one direction: wider than tall, or taller than wide, so the square symbol becomes a rectangle. Stretching distorts the module grid, and the scanner, which expects square modules in a square symbol, struggles or fails. The cause is almost always a layout step: the image was dragged to fit a box, a template distorted it, or a print setting scaled the axes differently. The fix is to restore the square proportions and to lock them in the layout.
Likely causes
1.
Image dragged to fit a box — Dragging a corner or a side handle in the layout stretches the code to fill a rectangular box. Test: compare the proof proportions with the original file.
2.
Template box with different proportions — A template image box that is not square forces the code into a rectangle. Test: check the template image box proportions.
3.
Print scaling with different axes — A print setting that scales width and height differently stretches the whole job. Test: check the print scale settings and measure the output.
4.
Curved or uneven surface — A code applied to a curved or stretched surface can distort after application. Test: check whether the distortion follows the surface curve.
5.
Proof never measured — A mild stretch looks plausible to the eye, so a visual proof check misses it. Test: measure the proof with a ruler.
Step-by-step fix
1. Measure the proof: width and height should be equal.
2. Compare the proof with the original file to confirm the stretch.
3. Find the step that stretched it: the layout, the template, or the print scaling.
4. Restore the square proportions and lock the aspect ratio in the layout.
5. Reprint one proof, measure it, and scan it on two phones.
6. Approve the run only when the proof is square and scans.
Putting this into practice
In practice, the ruler is the test that catches stretching. A stretched code can look almost right, especially when the distortion is mild, but the scanner reads the grid, not the appearance. Measure every proof, and lock the aspect ratio in the layout so the next edit cannot stretch it again. Keep a short note of what you tested, what failed, and what you changed, so the next person starts from evidence rather than guesswork. A fix that is written down survives staff changes and reprints; a fix that lives only in memory gets repeated.
Common mistakes to avoid
- Dragging a QR image to fill a rectangular box and distorting the module grid.
- 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 stretched will be used.
- Changing the artwork and the placement at the same time, so you cannot tell which change fixed a code that prints stretched.- Skipping the proof test because the change looked small, when small changes cause most repeat failures.
Quick checklist
- The proof measures square, width equal to height
- The aspect ratio is locked in the layout
- 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)
