I found the most reliable barcode scanner to be an old Symbol usb scanner. I also found that I could scan barcodes off of a screen with a laser scanner if I pu

I found the most reliable barcode scanner to be an old Symbol usb scanner. I also found that I could scan barcodes off of a screen with a laser scanner if I put a translucent white plastic bag over the screen. Maybe someone with more knowledge about optics could give some insight into why that trick works. My understanding is that laser scanners should only be able to scan by reflection, and shouldn't work off of a screen at all.