QR code not scanning? Diagnose the image and destination separately

Run a controlled comparison

1. Use a trusted reader and clean the lens. Frame the full code, hold steady and adjust distance until the camera can focus.
2. Compare the original file on a separate screen with the finished print under similar conditions.
3. Try a plain, dark-on-light version containing the same payload, with no logo.
4. Change one factor at a time and record the device, width, surface, lighting and result. A pass on one phone is useful evidence, not universal compatibility.

Inspect the pattern, border and surface

• Clear border: a conventional QR symbol needs a quiet zone four modules wide on each side. Keep neighbouring text, frames and patterns outside it. The safe-border option helps preserve it in the export.
• Contrast: begin with dark modules on a light, opaque background. Inversion, pale gradients or transparency over a busy surface can change what the camera sees.
• Geometry: avoid stretching, clipped corners, low-resolution screenshots and repeated compression. Preserve the square proportions.
• Placement: glare, curved containers, folds and textured surfaces can disrupt recognition. Test the code after application to the actual object.

DENSO WAVE explains the four-module quiet zone and symbol-area calculation. Error correction is not permission to cover a fixed percentage of image area: damaged functional patterns and the distribution of missing data matter. Remove the logo during diagnosis rather than treating a width percentage as a safe guarantee.

Calculate modules, then test the viewing distance

There is no universal centimetre minimum or distance ratio that guarantees phone scanning. The module count, camera, focus, print quality and surrounding light all matter. Treat a proposed size as a trial value, not a certified lower bound.

For a worked example, a 33-module symbol with four clear modules on each side spans 41 modules in total. At an overall width of 30 mm, each module is about 30 ÷ 41 = 0.73 mm. A 57-module symbol at that same width gives 30 ÷ 65 = 0.46 mm. These calculations explain why two codes printed equally wide can behave differently; they are not pass/fail thresholds.

In Print assistant, the requested width includes the border. Do not add a second border allowance to that same measurement. For a sign, test the intended viewing position and reachability; a small desktop sample does not establish poster performance.

Check the actual export and installation

1. Preserve the recommended border and inspect the downloaded image, not just the editor preview.
2. For SVG, set physical width in the design application. For print PNG, choose width and DPI, then review placement size. A DPI label alone does not increase pixel dimensions.
3. Print PDF signs at Actual size or 100%. Automatic fitting can alter the width you tested.
4. Scan the applied sample with representative devices and compare the decoded payload.
5. If decoding succeeds, separately test the webpage, draft message, contact import or Wi-Fi connection.
6. Recheck after changing a logo, payload, size, material or destination configuration.

Interpret eToolPlus checks accurately

Payload verified compares the rendered QR data with the entered payload. It does not test a URL’s safety, a router password, an installed app or outdoor durability. Ordinary image downloads may remain available when the automatic check fails; read the status. Print PNG and sign exports require a successful check, but still need a real-world trial.

For dense text or contacts, remove unnecessary fields or increase output/print size. If a URL is long, use a stable shorter address you control where appropriate. A shortener adds a service dependency, so consider link lifetime before printing.

Common questions