QR code

QR (Quick Response) codes are a two-dimensional bar codes that require dedicated QR bar code readers running on camera phones. QR codes store data in both dimensions (as opposed to traditional bar codes that only store data horizontally) with the highest storage capacity amongst current comparable two-dimensional codes.

Size requirements
Although some have suggested 0.5" for every foot a user is from the tag, our experience has shown that 1" per foot is optimal.

Contrast ratio
One of the most important considerations is contrast ratio. The QR tags should have a minimum contrast ratio of 4:1 and should be printed on material that can maintain this ratio despite physical, real-world conditions.

Placement & Printed Material
If possible, it would be optimal to avoid reflective/glossy material. In areas exposed to nature, there exists the potential of glare from sunlight. Furthermore, in dim light, some scanning apps will automatically turn on the camera light, causing a glare and possibly obscuring the QR code (of course this is dependent on the app, as well as the hardware of the smartphone).

QR codes should be placed on a flat surface, free of any wrinkles or extreme curves.

If directing users to a web URL, it should go without saying that QR codes should be placed in locations with mobile Internet access.

Customization & Branding
QR codes can be an integral part of a marketing strategy, and as such graphic design firms may be able to incorporate the bar code with corporate brands and logos. Some companies such as TIME magazine, Louis Vuitton, and WIRED magazine have chosen to use designer QR codes as complements of their marketing campaigns.

However, this is not suggested, because there is still the possibility that the overlayed graphic layers could block part of the QR code pattern (despite QR codes error correction capabilities and the possibility of user confusion (ie, "is that some strange art or something I can scan?").

Microsoft Tag High Capacity Color Barcodes (HCCB's) by nature are colorful and visually appealing, and may lend itself better to generating designer two-dimensional barcodes.

Comparisons
QR Code
 * Simple to generate code, but limited in its display (no customization of design)
 * Accessible readers – apps are available for nearly any smartphone
 * Content and information fed is limited
 * No true analytics through free usage (alternative: Google Analytics on mobile site)
 * Direct stores/embeds data into code
 * Published ISO standard
 * Slow scan, fast decode

Microsoft Tag
 * Simple to generate, not-so-simple to customize (you need to know graphic design and key elements)
 * Content and information can be updated
 * Stats reporting and expired linking
 * Limited apps
 * Indirect decoding (ie, requires Internet connection for decode)
 * Proprietary
 * Fast scan, slow decode

Android

 * QR Droid (scan, decode, and generate)
 * Barcode Scanner (scan)
 * QuickMark Barcode Scanner (scan)
 * ScanLife Barcode Reader (scan)