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Make the matrix lock on the first try

Distance, contrast, module density, and print quality decide whether a phone locks onto the code. Check the rules below before the run goes to press.

How large the code should be

Plan the code side at about the scan distance divided by 10. A scan from 100 cm needs about 10 cm of matrix plus a quiet zone. Windows and banners need extra margin, because phones are rarely held perfectly square.

What the camera actually reads

Inversion, light on dark, fails often. Skip weak contrast, a gradient under the matrix, and glossy laminates that throw glare. Dark modules on a light background stay the most stable for cameras.

Choosing L, M, Q, or H

From L to H, error correction adds redundancy: damage is tolerated more, and density goes up. M is often enough on clean print. A logo in the center or wear on the carrier calls for Q or H and a larger physical size. On qr-free.online, match the level to the job instead of always picking the maximum.

Files the press can hold

PNG fits screens and quick layouts. Keep the quiet zone, do not squeeze the code into a narrow column, and check that the press raster does not crush the modules. SVG is the right export for the press.

Proof it on real phones

If the URL must change after print without a new run, use a dynamic code on QRcode Global. Try 2-3 phones, from mixed distance and angle, in shade and in bright light.