6 min read
Can QR codes be coloured? Contrast rules that keep them scannable
QR codes can use brand colours, but scanners still need a reliable difference between the dark and light modules. Contrast is only one part of the real print test.
Keep a clear light and dark pair
Choose a dark foreground and a much lighter background. Avoid similar shades, gradients across the code, transparent backgrounds that reveal a busy surface, and pale modules on a dark field.
A numerical contrast ratio helps compare colours before export. QRnook treats 7:1 as strong, 3:1 as a caution threshold, and lower contrast as a serious risk; the scale is a practical heuristic for QR scanning.
Screen colour is not print colour
Paper, ink, coating, lighting and printer calibration can all shift the result. A screen preview cannot measure those changes.
Print a proof on the intended material and scan it with a phone. Keep a plain black-on-white alternative for situations where branded colour does not reproduce reliably.
Use styling carefully
Rounded modules, eye styles and logos alter the pattern. Keep the finder shapes recognizable, preserve the quiet zone and use the decode test after every meaningful change.
In short: Pick contrast first, then validate colour and styling in the final printed context.