A QR code is a grid of dark and light squares (modules) that stores a short piece of text. What that text is decides what the code can and cannot do later.
Static codes hold the content itself
A static code stores the content directly: a URL, a WiFi network and password
(WIFI:T:WPA;S:Cafe;P:latte;;), a contact card, a phone number. Nothing sits between the code and
the content, so it works forever and offline, and no service can turn it off.
The catch: it cannot change. A typo in the URL, or a new menu, means a new code and a reprint.
Use static codes for WiFi passwords, contact cards, and links that will not change.
Dynamic codes hold a short link
A dynamic code stores a short link, such as https://qrsome.com/r/k3X9mPq. Scanning it opens the
short link, which redirects to your real URL. Because the redirect lives on a server:
- you can change where the code points after it is printed;
- every scan passes through the server, so scans can be counted by day, country and referrer.
The trade-off is that the code depends on that short link existing. Delete the dynamic code and printed copies stop working. On QRsome that is the only thing that stops one: dynamic codes do not expire and have no scan cap.
Use dynamic codes for menus, flyers, packaging and anything printed in quantity.
Five rules for a styled code that still scans
- Dark on light. Phones look for dark modules on a light background. Light codes on dark backgrounds fail on many phones, so QRsome refuses them.
- Enough contrast. QRsome requires a contrast ratio of at least 3:1 between every foreground color (both ends of a gradient) and the background. Pastel on white does not make it.
- Keep the quiet zone. The margin around the code (2 modules by default) tells the camera where the code ends. Do not print text or borders right up against it.
- Logos need error correction. A logo hides part of the code. With a logo QRsome switches to error correction level H, which survives about 30% damage, and keeps the logo plate under 22% of the width.
- Size for the distance. As a rule of thumb, the code should be at least a tenth of the scanning distance: 2 cm wide for a business card read at 20 cm, 30 cm wide for a poster read from 3 m.
Rounded modules, dots and round eyes all scan fine when these rules hold. Every QRsome style is tested against two different decoders before it ships.