QR Codes on Posters

Size for the real distance, not the design view

The rule is one tenth of the scanning distance, and on posters that produces numbers designers resist:

• A3 on a community noticeboard, read at 0.5 to 1 m, needs 5 to 10 cm
• A2 or A1 in a corridor or foyer, read at 1.5 to 2 m, needs 15 to 20 cm
• A0 paste-up in the street, read at 2 to 3 m, needs 20 to 30 cm
• Anything above head height is read at a steep angle and needs to be larger again, or moved down

On an A1 poster a correctly sized code takes roughly a fifth of the width. That proportion is not a mistake in the layout. Shrinking it to make the design breathe is the most common reason a poster campaign produces no scans at all.

The paste-up problem

A poster pasted to a wall is not flat. It wrinkles as it dries, it follows the mortar lines of brickwork, and it lifts at the corners within a week. Every one of those bends the pattern.

• Put the code in the lower third, where paste-ups are flattest and where a passer-by can reach it
• Avoid the area over mortar joints and brick edges where the paper sits into a groove
• Oversize by about a quarter compared with a flat print, so the pattern survives some distortion
• On corrugated or textured hoardings, the surface carries its own competing pattern; a code needs to be considerably larger there or moved to a smooth panel

Posters are read at night

This is the difference between posters and almost every other print surface. Street posters do most of their work after dark, lit from one side by a street lamp or a shop window.

• Pure black on white, never a dark brand colour on a darker background
• Matte stock. A gloss poster under a sodium lamp reflects straight into the camera
• Check the site at night before booking a run, because a poster in a doorway with no light is a poster nobody scans
• Avoid printing the code where the light falls at a glancing angle, which turns every wrinkle into a shadow across the pattern

Track each site

A poster campaign normally reports nothing until sales move, if then. A distinct dynamic code per site changes that within days:

• Which streets produce scans, and which are decoration
• What time people scan, which is almost always later in the evening than anyone plans for
• Which creative works, when two designs run in the same area
• Whether the site was flyposted over, which shows up as scans stopping dead

What the scan should open

The reader is standing in the street with one hand free. Keep it short: an event page with a date and a ticket link, an offer, a signup, or a map to the venue. A homepage asks them to navigate while standing on a pavement, and most of them will not.

Give it a caption. "Scan for tickets" outperforms an unlabelled square by a wide margin, especially at night when nobody wants to stand there guessing.