QR code colours: what scans and what does not

The rule: dark modules, light background

Scanners look for dark squares on a light background. The classic black on white is the safest. You can use colour, but the code must stay clearly darker than its background. Inverted codes (light on dark) fail on many scanner apps.

A black QR code with rounded corner squares on a white card in QRinst — High contrast baseline: near-black modules on white.

A colourful example, tested

Here the finder squares are teal and the data modules olive green. It looks friendly, but the olive is noticeably lighter than black.

A QR code with teal corner squares and olive green data modules — Looks fine to the eye. Does it scan reliably?

Uploading it to the QR checker gives a useful answer. It decoded the link and measured about 66% contrast, which passes, but it still returned Scannable with Recommendations because of a margin warning. That is the point of testing rather than guessing.

QR checker result: Scannable with Recommendations, valid web link, quiet zone warning, contrast about 66 percent — QR checker result for the coloured code.

Practical tips

Keep every module darker than the background, not just the corners.
Avoid light grey, yellow or pastel on white.
Keep the white margin around the code; do not place colour right against it.
Print colours look different from screens, so print a proof and scan it.
When in doubt, go darker. See why a QR code is not scanning.

How scanners see colour

A phone camera turns the image into black and white before it reads the pattern. It decides, square by square, whether each one is dark or light. Colours that look different to your eyes but have a similar brightness, such as red on dark green, can come out as the same grey and merge together. What matters is the difference in brightness, not the hue.

A good test is to look at your design in greyscale. If the pattern is still obvious as dark against light, a scanner will cope. If it fades, change the colours.

Safe and risky combinations

Safe: black, navy, dark green or dark brown on white or cream.
Usually fine: a deep brand colour on white, if it is dark enough.
Risky: mid-tones such as orange, light blue or lime on white.
Avoid: yellow, pastel or grey modules, and anything on a photo or gradient background.
Avoid: light modules on a dark background, which many apps cannot read.

A coloured background is fine as long as it stays light and flat. A busy or patterned background behind the code interferes with the quiet zone, so place the code on a plain white or light panel.

Colour on screen versus on paper

Screens glow and paper reflects, so the same colour looks different in each. Inks also dry lighter than they appear in a design file, and glossy surfaces add glare. A code that scans comfortably on your monitor can lose contrast in print. Print a proof on the final stock, check it in the lighting where it will be used, and compare it with the guidance in the print size guide.