QR code not scanning on a screen, monitor or TV
Scanning a code off a screen is harder than off paper. Glare, a screen that flickers on camera, and a code that is too small on a big display all get in the way.
A few small changes make screen codes work.
Why does a QR code not scan from a monitor or TV?
Screens flicker at the camera's shutter speed, create glare and moire patterns, and show the code small relative to the room.
- Increase the brightness.
- Dim room lights that reflect on the screen.
How big should a code on a screen be?
Make it large and high contrast: black on white, with a clear white border. On a TV or presentation, fill about a quarter of the screen height.
Can I scan a code on the same phone?
No. You cannot point the phone at its own screen. Use a link or a share button for that, or take a screenshot and open it in a scanner that reads photos.
What helps in a presentation?
Leave the code on screen for at least 20 seconds, add the web address as text beneath it, and test it from the back of the room.
Questions
Does a dark mode screen hurt scanning?
Yes, an inverted code (light on dark) is not read by every scanner. Use dark on light.
Why does the code look fine but not scan?
Moire patterns or a flickering screen. Change the angle.
Does screen size matter?
Yes. A tiny code on a big display is hard to focus.
What about a code in a video?
Hold it on screen long enough and keep it still.
Can I print the code instead?
Yes. A printed code is more reliable than a screen.
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