Demystifying 2d Codes
If you’ve worked with linear bar codes, you’re more familiar with 2d codes than you may think.
Quiet Zone: Barcodes require a sufficient quiet zone, and 2d codes do, too. The rule of thumb is to have a minimum white border equal to the width of two (and up to four) modules around all four sides.The old saying is true—the more things change, the more they stay the same. Similar thinking can be applied to 2d codes. 2d codes are a lot like bar codes, which you may already familiar with. Applying that thought process will remove a lot of the mystery when working with 2d codes.
Symbol Contrast: Symbol contrast is the difference in reflectance values between the lightest and darkest parts of the symbol. The blackest possible bars printed on the whitest possible substrate would have 100% contrast. Gray shades can be used, as long as the background and module colors vary in contrast by >=40% (a “C” grade).
Color Usage: Like bar codes, QR codes do not need to be black and white—as long as there is sufficient contrast. It’s best to stick with a light colored background towards the red end of the color spectrum and use dark colored modules towards the blue end of the color spectrum.
Verification: Test the 2d code on a variety of mobile devices, and test scanning it with a variety of reader apps. A professional grade GS1 bar code scanner is a great verification tool—especially if reporting and ISO compliance are necessary. As an example, in addition to verifying all of the major (linear) bar codes, the Integra 9500 will read and verify QR codes, Micro QR codes and Datamatrix codes.