QR codes on product packaging: a manufacturer's guide

A QR code on packaging only works if it's placed where people can scan it comfortably, printed with enough contrast and size, labeled with what the customer gets, and tested on real print before the full run. If every unit carries its own unique code, you also need to keep codes from being scanned on the shelf and keep tight control of the code data at the printer. Here's how to get each part right.

Decide what the code is for

A code on a package is a promise printed thousands of times. Reprinting is painful, so settle the purpose before the artwork:

• Product information - manuals, ingredients, recipes, care tips. One code per product line is usually enough.
• Registering or verifying a specific item - a product authentication QR code needs a unique code on every unit.
• A promotion or collectible reward - also unique, and hidden from anyone who hasn't bought the product.

For the customer's side of the experience, see how QR codes on products work. This article is about the manufacturer's side.

One code per product vs one code per unit

A shared code is simpler and cheaper to produce. Unique codes are worth the extra effort when it matters that this customer holds this exact item - for rewards, registration or authentication.

Where to place the code

Shared codes

• On the front or side panel, visible on the shelf and at home.
• On a flat area, away from folds, seams and crimps.
• Clearly separated from the barcode so neither cashiers nor customers mix them up.

Unique codes

• Inside the pack - the inner lid, a flap or an insert card. That way nobody can use the code without buying the product.
• Under a protective layer - a scratch-off panel or a tear-off tab when the pack can't be opened before purchase.
• Outside, just a hint - a short line on the visible side is enough: "Your collectible code is inside."

Designing a code that scans

• Contrast. A dark code on a light background is the safest choice. Inverted codes (light on dark) aren't read by every camera.
• Quiet zone. Leave a clear margin around the code with no text or patterns. Scanners use it to find the edges.
• Size. The farther from the eye the code will be, the bigger it needs to be. On small packs, resist shrinking it to the minimum - test on several phones at a normal distance.
• Short links. The shorter the URL encoded, the simpler the pattern and the more reliably it reads at small sizes.
• Logos with care. QR codes can recover from some damage, but a large logo in the middle can push a code past what scanners tolerate.
• A clear label. Say what people get and where they'll land. Printing your official domain next to the code helps people trust it.

Materials and printing

Packaging throws problems at a QR code that a screen never does:

• Gloss and laminates create glare. A matte patch under the code helps.
• Curves on bottles, cans and tubes distort the square. Run the code along the less curved axis or make it larger.
• Foil and metallic finishes scan poorly. Print the code on a solid white underlay.
• Transparent materials let the contents show through. Add an opaque backing.
• Fine screening and misregistration blur the modules. Print the code in a single solid ink where possible.

Printing unique codes

Unique codes are produced with variable data printing on digital presses or supplied as separate labels and insert cards. Agree on the details with your printer before production:

1. How the code file is handed over, and in what format.
2. How they confirm each code is printed exactly once, with no gaps.
3. What happens to spoiled sheets - codes on them must be accounted for or disabled.
4. How the code file is stored after the job. Treat it as sensitive: until a code is activated, anyone who has it can use it.

Pre-press checklist

1. Scan a proof with several phones, old and new, under different lighting.
2. Confirm the link opens the right page and that the page works well on mobile.
3. For unique codes, activate a few test codes and check that a second activation is refused.
4. Look at the pack as a shopper would: is it obvious what the code gives and where to find it?
5. Make sure the page will stay live for as long as the product sits on shelves and in people's cupboards.

Keeping customers safe

Packaging passes through many hands, so build in some protection. Print your domain near the code so people can match the address after scanning. If a code is single-use, say so plainly and tell customers not to share or post it before activating it. More tips for shoppers are in QR code safety.

How Crypto Sticker does it

Brands that want to give customers a collectible reward place a Cryptoscope QR code on their product. The customer scans it, signs in or registers on cryptosticker.org, and a digital collectible sticker appears in their personal collection. Once activated, the code stops working, which is exactly why it belongs inside the pack or on an insert rather than on the outside.

Every sticker has a unique serial number and a public passport page in the registry - see digital passport. The passport confirms that the registry entry exists, but on its own it doesn't prove ownership; ownership is shown in the owner's personal collection. For the bigger picture beyond a single code, read connecting physical products to digital collections. To discuss putting codes on your own products, visit Crypto Sticker for business.

A Crypto Sticker is a virtual collectible and an entry in a private registry. It is not a bank account, electronic money, cryptocurrency, a security or an investment product.