Packaging artwork preflight
Check one QR Code's module size, quiet zone, contrast, encoded URL, and catalog GTIN before plates are cut. The image is analyzed in your browser and is not uploaded to Stampwright.
Current scope: QR Code only. This tool does not decode GS1 DataMatrix, find every barcode in the artwork, or verify a printed sample.
We need the intended printed width to convert pixels into millimeters. If you leave it blank, the encoded data can still be checked, but the physical size cannot.
What each check means
Module size, also called X dimension
A module is one square of the matrix. Everything about whether a scanner can read the symbol follows from how big that square is once it is printed, which is why the tool asks for the intended printed width rather than reading the pixel dimensions alone.
For the GS1 retail point of sale application profile the range is 0.396mm minimum, 0.495mm target, and 0.99mm maximum. Below the minimum, checkout scanners start failing on the first pass. Above the maximum, the symbol may exceed the scanner's field of view at the working distance a cashier actually uses.
The low end is easy to cross without noticing. A designer scales the QR Code to fit a crowded panel, the module drops under 0.396mm, and nothing on screen looks wrong, because a monitor renders a small module perfectly well.
Quiet zone
The empty margin around the matrix. GS1 requires 4 modules on every side, and it must be genuinely empty: no text, no keyline, no background pattern, no adjacent barcode crowding in.
The quiet zone is easy to lose late in a project, because nothing about the symbol has to change for it to disappear. A keyline added at the last proofing round eats into the margin while the QR Code itself stays exactly where it was.
Contrast
The luminance difference between the dark modules and the background. GS1 guidance treats 30% as a minimum input and about 50% as the level to aim for.
Read this number as a screening estimate only. A real symbol contrast grade comes from ISO/IEC 15415 verification under controlled 660 nm illumination on the printed piece. A browser reading a digital file cannot produce that grade, so this tool warns rather than claiming a pass or a failure.
Dark-on-dark is the usual trap: a navy matrix on a black panel measures far worse than it looks on a backlit monitor.
Encoded URL
The tool decodes what the symbol actually contains and checks it against GS1 Digital Link syntax. Artwork and data drift apart more often than teams expect, because the URL is embedded in an image early and the catalog keeps changing afterwards. To check a URL you have as text rather than as a symbol, use the Digital Link syntax validator.
Catalog GTIN match
If you supply the GTIN this pack is for, the tool compares it against the one encoded in the symbol. A mismatch here means the artwork carries another product's identifier, which is the failure that is most expensive to find after a print run.
What this tool cannot do
- It does not verify a printed sample. Ink spread, substrate, and press variation are real and none of them exist in a digital file. Scan a printed sample before a production run.
- It reads QR Code only. GS1 DataMatrix is out of scope for now.
- It checks one symbol. It does not sweep a full artwork file for every barcode present.
- It cannot grade the symbol. ISO/IEC 15415 needs a verifier and a printed piece.
- It says nothing about the rest of the catalog. The free readiness audit checks every row for invalid GTINs, duplicates, and destination problems.
The image file stays in your browser and is never uploaded. Decoding and measuring happen on this page. To return a verdict, the page then sends us the measurements above, the decoded text of the QR Code, and the expected GTIN if you entered one.
Of that, we keep the verdict, the measurement values, and the length of the decoded text. We do not keep the image, the decoded text itself, or the expected GTIN. The privacy notice sets this out in full.
Background reading: QR Code print requirements and running a UPC and a QR Code together.