QR code printing checklist

Check the fundamentals that scanners depend on.

Size is the one item on this list you cannot fix after the fact. The working rule is a 10:1 ratio: one unit of code width for every ten units of scanning distance. A code people read from 60 cm wants to be around 6 cm across; a poster read from three metres needs roughly 30 cm.

A code that is too small cannot be rescued by contrast or error correction. The camera cannot resolve the modules, and no amount of styling will bring them back.

A code that scans perfectly on a monitor can still fail because of what it is printed on. Glossy laminate and varnished stock reflect light straight back at the camera, which is why matte finishes hold up better outdoors and under spotlights.

The other failures are structural. A code printed across a fold or a seam is distorted, and one printed on dark material needs a light panel behind it — scanners expect dark marks on a light background, and simply lightening the modules is not the same thing.

Export a vector file — SVG, PDF or EPS — and let the printer scale it, so the modules stay sharp at whatever size you need. A small raster image scaled up is the most common cause of a code that looks fine in the layout and blurs on the shelf.

If the job prints in process colour, ask for the code in pure black rather than rich black. Four-colour black is built from several inks, and if they misregister by a fraction the module edges soften.

Test the physical print with at least two phones and in the lighting conditions it will live in — a laminated sign in sunlight behaves differently from a screen.