QR codes on wedding stationery: sizes, colours, and what to link to

Point the code at a page on the couple's own wedding website, not directly at the photo-sharing service, the gift registry or the RSVP tool. Two reasons. Those services change their links, close, or start charging, and a code printed on 120 place cards cannot be edited. And a wedding website address is short, which makes a smaller, simpler code that scans more easily at place-card size.

So: rowanandellis.wedding/photos on the card, and that page links onward to whichever album the couple is using this year. If they move the album, they edit one page. The stationery is untouched.

The same logic is why we only make static codes, which have the address in the pattern itself and never expire, rather than dynamic ones on a subscription. The longer version.

A code scans comfortably from about ten times its own width, and most phones will not focus closer than about 10 cm. So the practical floor is 2 cm across for a code that will be scanned in the hand, and the shorter the address inside it, the more forgiving it is.

• Place cards and favour tags: 2 to 2.5 cm. Use the shortest address you can.
• Invitations, details cards, orders of service: 2.5 to 3.5 cm.
• Table numbers and menus: 4 to 6 cm.
• Welcome signs and seating charts: 10 cm or more, read from a metre away.

Always place the code as an SVG or PDF and size it in the artwork. A PNG scaled down looks fine on screen and prints with grey edges, which is the usual cause of a code that scans on the proof and not on the letterpress.

Phones read the difference between the dark squares and the light background. They do not care about the hue; they care about the contrast. So the rule is: code clearly darker than its background, by a wide margin.

• Works: navy on ivory, forest green on white, burgundy on blush, charcoal on sage, black on kraft.
• Does not work: sage on blush, dusty blue on grey, gold foil on anything, white on any pale colour, any two mid-tones together.
• Inverted codes (light squares on a dark background) scan on most modern phones but not all; avoid them on anything a grandparent will scan.

Metallic foil and spot varnish reflect the phone's own light back at it, so a foiled code often fails under a downlight. Print the code in flat ink and foil the monogram instead.

A monogram in the centre of the code works because QR codes carry built-in error correction: at the highest level, about 30 percent of the pattern can be missing and the code still reads. The logo spends some of that allowance. Keep it to about a fifth to a quarter of the code's width, give it a small pad of the background colour, and keep the mark itself simple. A single initial or a crest reads well; a three-word script name does not, at any size.

If the code will be very small, leave the monogram off. At 2 cm the logo is a few millimetres across and adds nothing except risk.

Every code needs clear space around it, at least four of its small squares wide on every side, in the background colour. A border, a floral illustration or a line of text running into that space is the most common reason a beautifully designed card will not scan. Our files include the margin; leave it alone in the artwork.

Print one proof on the actual stock, and scan it with two phones, one of them older. Check the code opens the intended page, not just any page. Do it again with the first finished card. It takes two minutes and it is the difference between a happy couple and 120 reprints.

If you make stationery and add codes to most orders, our packs are priced for that: codes for planners and stationers, from 30p each. For a single wedding, one code in your colours is £1.