I just downloaded the enhanced certificate with the QR code to my computer.
One of the requirements on the website is that the QR code be no smaller than 60 x 60mm.
When I print the certificate on a standard letter size piece of paper, the QR code is just 60x60mm
So far so good.
But I wanted to reduce the size so it's the same saize as the passport and then place it in the back of the passport with a paper clip so it's always there for travel.
The QR code is then only about 30x30mm - anyone know if that will still work?
My smartphone screen (Samsung S4 mini) is also not 60mm wide so I have to reduce the QR code to less than 60mm there.
General question - In practice, how small can the QR code be and still be readable?