Tips for Printing “Well-Rounded” QR Codes on Objects

Coca-Cola does it. KFC does it, too. There’s no reason why you and your clients shouldn’t benefit from the use of QR codes on cups, hats or other promotional items as well.

Bearing in mind the #1 rule of QR code marketing: Make it worth my while! (I know you will not simply send people to your website.)

Rule #2 is equally important though: Ensure the code is readable. Nothing is more frustrating than getting out your smartphone, opening the scan software and not getting anywhere (see “Don’t sabotage your QR code”).

Readability is a simple enough problem to solve. You can basically print QR codes on anything, but they work best on flat, non-textured and non-shiny surfaces. That's why we see a lot of QR codes on t-shirts and posters, but not so much on cups and mugs. (Notice I didn’t use the word “never” here.)

Last fall, Coca-Cola produced special Slurpee and Big Gulp cups with a QR code that downloaded an interactive app called Snowball Effect. The whole campaign tied into prizes for customers and benefits for the World Wildlife Foundation.

The Well-rounded QR code
Curved and shiny surfaces, however, present challenges for readability. So I turned to digital printing industry analyst and QR-code specialist Heidi Tolliver-Walker for some “well-rounded” insights.

Q: Heidi, let's talk about QR codes on cups and mugs. Does the curvature of the cup mean you cannot print QR codes on them?

Heidi: It's been done, but you have to do a lot of testing. It's important to test different sized codes on the actual mug on which you will be printing (or at least the same size equivalent) and see what works. On a mug, smaller is often better, but you don't want to print it so small that the camera doesn't get enough detail either. You have to play with the size and see how large you can make it while still making it readable on the largest number of phones.

Obviously, the best option is to print codes on the actual mugs to test them. Some people print out their QR codes on paper and tape them to the mug. It's not very sophisticated, but it can work. The challenge is that there is a gloss factor here, as well. I don't know whether people are covering their codes with plastic wrap to simulate the gloss, but it might be something to try.

Q: How big should the code be to be readable?

Heidi: One rule of thumb is to make sure the code doesn't take up more than one-third of the visual space. On a coffee mug, for example, this might be 1˝ square. If you print a 3˝ QR code on a 3.5˝ diameter mug, you're going to have a problem.

Q: Would using a shorter URL (like with bit.ly) make the QR code easier to read?

Heidi: That is one of the best practices for QR codes for sure. Not only do URL shorteners make the codes simpler and easier to read, but they also provide tracking for free.

Q: Does the above apply to paper cups as well as coffee mugs?

Heidi: In terms of the curvature issues, yes. But paper cups have one benefit over ceramic and other mugs, which is the lack of gloss. Surface shine can impact readability. When you're working with objects that reflect light (for example, a glossy mug, but also something under glass like a movie poster), remember that negatively impacts readability. Paper mugs don't have that problem. Then again, most people don't keep them in their cabinets either!

Q: And what about wine labels? They’re on a somewhat curved surface.

Heidi: The same rules apply. Use a URL shortener; keep it to within one-third of the visual space; and test, test, test. You may also want to avoid gloss coatings.

Remember, whatever your code size, substrate or color, make sure to test, test, test. Use an iPhone. Use a Blackberry. Use an Android operating system. Just Test.