QR code size, contrast and placement: a printing checklist

The 10:1 distance rule

As a working rule, a QR code needs to be roughly one tenth of the intended scanning distance. A code scanned from arm's length (about 300 mm) can be 30 mm across. A code on a lift lobby wall read from two metres needs to be around 200 mm.

Designers routinely violate this by dropping a 40 mm code onto an A3 poster. It looks balanced on screen and fails in the room.

• Counter sticker, 250–350 mm distance: 30–40 mm code.
• Table tent, 400–600 mm: 40–60 mm code.
• Reception sign, 700 mm–1 m: 70–100 mm code.
• Wall poster, 1.5–2.5 m: 150–250 mm code.

Quiet zone and module size

A QR code needs a clear margin of at least four modules on every side. A module is one of the small squares in the pattern. Text, borders and background photography inside that margin reduce the reliable scanning distance sharply.

Keep the printed module size at or above roughly 0.6 mm for offset or digital print. Below that, ink spread on uncoated stock starts merging modules.

Contrast and colour

Dark pattern on a light background is the only reliably safe combination. Inverted codes — light modules on dark — scan on many phones and fail on enough of them that they are not worth the aesthetic.

Aim for a contrast ratio comfortably above 4:1 between module and background. Brand colours are fine as long as the dark side is genuinely dark; mid-tone teal on cream is the classic failure.

Materials and finish

Matte or satin laminate is worth the small extra cost. Gloss laminate under directional lighting produces a specular hot spot exactly where the camera needs detail, and it is the single most common cause of a code that “only sometimes works”.

Wet or humid areas — bathrooms, poolside, outdoor tables — need waterproof vinyl. Standard paper stock curls, and a curled code distorts the pattern geometry.

Choosing surfaces

Rank candidate surfaces by dwell time first. Where does a customer stand still, seated or waiting? Those places outperform high-traffic walkways every time.

Then check the eye line. A code below waist height on a counter front is invisible to a standing adult holding a phone. Angle it, raise it, or move it.

FAQs

What is the smallest a review QR code can be?

For hand-held distances, around 25–30 mm across on good stock. Below that you are relying on the customer moving the phone very close, which most will not do.

Can I put a logo in the middle of the code?

A small centre logo is usually tolerated because of built-in error correction, but it consumes error-correction budget that print imperfections also need. Keep it under about 15% of the code area.

Does a coloured background break scanning?

Not if the contrast between the modules and the background stays high. Test the exact printed artwork, not the on-screen version.