Designer QR Codes make your campaigns stand out compared to simple black&white QR Codes. However, be careful when creating Designer QR Code because some devices might have problems to decode them.
The more designer elements you add to the QR Code, the more difficult the QR Code becomes to read. Also note that not all QR Code Readers can decode the Designer QR Code equally well. If there is a reading problem with a QR code, reduce the design elements, remove or reduce the size of the logo and try scanning the QR code again.
Possible reasons for readability problems
The logo in the QR Code is too big
A logo helps to brand your QR Code or gives an intention to the user why to scan the QR Code. However, if the logo is too big, the QR Code cannot be read anymore. Remove or resize the logo and try to scan the QR Code again. Logos work best when they are centred in the QR Code and they may not be bigger than 30% of the QR Code area.
A maximum of 30% of the QR code can be overwritten with a logo so that it still be readable Too many design elements such as round or polygon symbols are used in the QR Code
Designer QR Code can get very creative - maybe too creative sometimes. Reduce the design elements and effects one by one and try to scan the QR Code again until he is readable.
The colors have too little contrast with the background
Make sure that the colors of the individual elements have enough contrast with the background color. If a QR Code distinct too little of the background it might not be readable.
Some QR Code Readers cannot decode a white QR Code on a black background (inverted)
Most QR Code Readers can decode QR Codes with inverted colors as well as the native camera app. However, there is a small number of Apps that cannot decode such QR Codes. If you want to make sure that the code can be read by all scanners avoid inverted colors.
Old smartphone with a poor camera resolution
Remember when creating Designer QR Codes that some people might have old phones with a poor camera solution where the QR Code cannot be encoded. A good practice is to test your QR Code also with older phones, if the QR Codes work there you are safe.
The QR Code Reader app has a bad algorithm to decrypt the QR Codes
Even modern phones have a built-in QR Code Reader in the native camera app, they algorithms differ from device to device. The more devices you are using for testing the more you can make sure that your Designer QR Codes are working for all users.
Summary
The safest variant that a QR Code can be read by all readers, is the Standard QR Code or the Transparent QR Code.
The less complex the QR Code, the easier it is to decrypt it. Designer QR Codes are more difficult to decode, so the scan position, the angle of the camera to the QR code and how far the camera is from the QR code matters.
How well a QR Code can be read also varies from app to app and algorithm to algorithm.
Test, test, test
At each design step, test whether the QR Code is still readable and only after then add a new design element.
Basically, you should always test with a smartphone with a poor camera and apps with weak decoding algorithms. If the Designer QR Code can still be read, you are on the safe side.