Printing a QR code: size, contrast and margin.

A QR code reads or doesn’t read depending on one thing: the size of its little squares once printed. A typical phone needs four tenths of a millimetre per square at the very least, and only works comfortably from half a millimetre up. Below the minimum, you need perfect conditions: good light, a recent device, a steady hand, crisp ink. On a card or a flyer, two centimetres a side puts you well above half a millimetre. That’s your floor, not your target.

• Two centimetres a side at minimum on anything held in the hand
• On a shop window or a vehicle, go bigger: people scan from further away
• Those two centimetres are for the code alone, the white border comes on top

The white frame around the QR code is what lets the phone know where the code begins. A designer who trims it to save space, or who places the code on a photo, breaks the code without anything showing on screen. Same thing for distortion: a QR code scales up as a square, never as a rectangle.

• Keep the whole white border, without cropping
• A plain, light background under the code, never a photo
• Scale it up keeping the square, without stretching

Download the vector file: it’s an outline, not an enlarged image, and it prints just as sharp on a three-centimetre sticker as on a three-metre banner. The image is fine for a screen, an email or a document, but it blurs as soon as you enlarge it. Your printer, though, wants the vector.

• The vector file for anything going to print
• The image for a screen, an email, a document
• A dark code on a light background: it’s the contrast that reads, not the colour

This is the check that costs dearly when forgotten. Have ONE copy printed, at its final size and on the final paper, and scan it with two different phones in the light it will live in. Check the page that opens, not just that it beeps. Only then, launch the five hundred.

• One copy, at the size and on the paper of the run
• Two different phones, in the real light
• Check the page that opens, not just that the phone reacts

Nobody points a camera at a black square out of curiosity. Write next to it what it opens: the menu, your work, your contact details. And if the destination changes one day, your QR code doesn’t: you redirect it to another page from your account, without reprinting a single sheet.

• A sentence next to the code, saying what opens
• A different code per medium, to know which one is really working
• A destination you can change after printing, without a new run