How to Test a QR Code Before Printing It

Why a screen test isn't enough

A screen emits light; paper reflects it. A code that reads fine as a backlit image on a monitor can lose contrast once printed, especially with colored inks, textured paper, or a printer that runs low on toner. The only reliable test is a physical print, at the actual size the code will be used.

The pre-print checklist

1. Print at actual size — not scaled on a preview screen. If the final use is a 10cm poster, print a 10cm test, not an A4 sheet with the code shrunk into a corner.
2. Test with at least two different phones — an iPhone and an Android device. Camera hardware and the default camera app's QR recognition differ enough between manufacturers that a code can scan instantly on one and struggle on another.
3. Test in the actual lighting the code will be used in — bright sunlight, dim indoor lighting, or under fluorescent office lights all affect how a camera reads contrast. A code tested only under a desk lamp can fail outdoors.
4. Test from the real scan distance — up close for a business card, from across a room for a poster. Scanning a poster-sized code from 10cm away tells you nothing about whether it works from 2 meters.
5. Check the destination loads correctly — not just that the scan registers, but that the link opens the right page, the WiFi actually connects, or the contact card saves with the correct details.

Common reasons a code fails only after printing

• ▸Low print resolution — exporting as PNG at a small size and then stretching it for a larger print blurs the module edges. Always export as SVG when the final print size isn't known yet, or export PNG at the exact target resolution.
• ▸Insufficient quiet zone — the blank margin around the code. If text, images, or a border are placed too close to the code's edge, scanners struggle to isolate the pattern. Keep a clear margin at least as wide as four modules on every side.
• ▸A logo that's too large — most scanners tolerate a logo covering up to roughly 30% of the code's area, relying on built-in error correction. Beyond that, the code loses enough data to fail.
• ▸Lamination glare — a glossy laminate under direct light can create a reflection that obscures the camera's view of the pattern. Matte lamination is more reliable for codes used outdoors or under bright lights.

Testing your code from oh my qr

Download your code as SVG, print a sample at the real target size, and run through the checklist above before sending it to a full print run. If a test fails, the most effective fixes, in order of impact, are to shorten the destination URL, increase the print size, reduce or remove the logo, and switch to the Square dot style if you're using a decorative one.