Many of you are aware that 2D barcodes--which look like waffles--are becoming ubiquitous for location-based services, mobile commerce, and increasingly point-of-sale and track and trace applications.

Did you know that there are many more you cannot see? They're covert 2D barcodes. And the master at providing reading equipment to find these hidden waffles is John Hattersley of InData Systems. I've had the pleasure to work with him on "ink-specific handheld readers". The concept is simple. The barcode reader has LEDs (or other light source) built-in that are tuned to the excitation bandgap of the covert ink (usually in the UV band), and bandpass filters tuned to the (higher-wavelength) reflected light.

See InData System's brochure (attached below) on John's presentation at the upcoming ITI Security Printing Conference (see http://www.communities.hp.com/online/blogs/securityprinting/archive/2009/09/12/imi-s-security-printing-conference-nov-16-18-2009-baltimore-usa.aspx) for more details. And enjoy the waffles.

Cheers,

Steve