So I have been building a free browser-based QR code generator for the past few months. It supports custom gradients, image overlays, and different dot shapes. The results look cool—think nebula images fading into purple gradients.

I was happy... until I tried to actually use one.

The "iPhone Failure" 📱

I tried scanning one of my cooler designs on my iPhone and it just did not scan. At all. WhatsApp failed. Some Android scanners worked, some didn't.

I set the error correction to Level H (the max 30% recovery level). Still nothing.

The Real Culprit: Contrast Detection

I spent hours thinking it was a bug in my library. It wasn't.

Phone cameras don't read QR codes like humans.…