Can a QR code be any colour?

The one rule: dark on light

A phone reads a QR code by telling dark squares from light ones. It does not care about the colour itself. It cares how dark each part is.

So navy, dark green, deep red, purple or brown dots all work, on white, cream or a light pastel background.

What to avoid

• Light dots on a dark background. This is called an “inverted” code. Some phone cameras read it, but many do not. It is not worth the risk on print.
• Two colours of similar darkness. Red on green, or blue on purple, can look bold to us but grey-on-grey to a camera.
• Pale dots. Yellow, light pink and light grey dots fade into a white background.
• Busy backgrounds. A pattern or photo behind a plain code makes the edges hard to find.

How much contrast is enough?

Designers measure contrast as a ratio. Black on white is 21 to 1. Two of the same colour is 1 to 1.

QRVivid warns you when the dots and background fall below 4 to 1. For printed codes, aim much higher. Darker dots scan faster and from farther away.

Can white on black work at all?

Sometimes. Some newer phones can read it. But older phones and some scanner apps cannot. If your design really needs a dark background, put the code on a white box inside it. You keep your design and the code scans everywhere.

Gradients and corner colours

A gradient from one dark colour to another dark colour is fine. Just keep both ends dark.

The three big corner squares can have their own colour too. Keep them dark as well. Phones use them to find the code.

Test in the real world

Colours look different on screen and on paper. Print a test page. Scan it under the light where it will hang: shop lights, daylight, or a dim restaurant. If it is slow, make the dots darker.

In QRVivid

Choose Styled code, then set the dot and background colours. If you pick light dots on a dark background, or colours too close together, QRVivid tells you right away.