> For the complete documentation index, see [llms.txt](https://docs.sqr.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sqr.co/questions-and-answers/about-qr-codes-in-general/what-should-i-know-before-printing-my-qr-codes.md).

# What should I know before printing my QR codes?

You need to know the right size, and the right contrasting colors, and always test it with your own phone before printing your custom-designed QR codes. If a QR code isn't working play around with the "Quality settings" this might help you without changing the colors.