QR codes on signs

What a sign code should open

Signs work around the clock, so think about the person who scans when you're closed:

• Your menu, hours or booking page, with a website QR code
• A way to call first thing, with a phone QR code
• A pre-filled text for quick questions, using an SMS code
• The listing page for the property on a real estate yard sign

Label it for that moment: Closed? Scan to book. Scan for tonight's menu. Scan for listing details.

Size it with the 10:1 rule

Signs are read from farther away than almost anything else on this list. The code should be at least a tenth of the scanning distance, a rule the size and printing guide explains in full.

• A door decal read at the door, about 50 cm away: at least 5 cm (2 in), and 10 cm is friendlier
• An A-frame on the sidewalk, read from 1 to 1.5 m: 10 to 15 cm (4 to 6 in)
• A window sign read from the far side of the sidewalk, about 3 m: 30 cm (12 in)

Yard signs are usually 45 by 60 cm (18 by 24 in), so a code sized for street distance would take over the whole sign. Most people walk up to scan one, so 15 to 20 cm works if the label invites them closer.

Nobody should scan from a moving car. For signs aimed at drivers, a short web address they can remember does more than a code.

Reading through glass

Window and door codes have a particular problem: the camera has to read the pattern through glass, past reflections from the street, tint and fingerprints.

• Mount the decal on the inside face of the glass, where weather and window scrapers can't reach it. Order it as an inside-glass decal, printed in reverse so it reads the right way round from outside.
• Ask for a solid white backing layer. A clear decal lets the dark shop interior show through the pattern and wrecks the contrast.
• Keep it off tinted or frosted film, which dims the pattern.
• Place it at eye height, roughly 1.2 to 1.6 m, and away from the patch of glass that catches afternoon sun.

Weather and wear

Outdoor signs need outdoor materials: vinyl with UV-resistant ink and a laminate, not paper in a plastic sleeve. Sun fades dark ink over months and rain warps paper. Choose matte over gloss, keep the pattern near-black on white, and set error correction to Q or H so a scratch or splash of mud doesn't kill the scan.

Test it from the sidewalk

Before you order, print the code at final size on paper, tape it where the sign will go, and scan it from where people will actually stand, once in daylight and once after dark. If the night scan fails, add light near the sign or move the code to where the light already falls. Then order the real sign.