1. A product label that discourages the counterfeiting thereof, comprising a first image printed on the label and having a first level of spectral reflectivity, a second image printed atop the first image by a thermal printer using ink having a spectral reflectivity different from the spectral reflectivity of the first image, the difference in spectral reflectivity being of a magnitude that the counterfeiter is unable to discern the presence of the thermal printed second image and will therefor counterfeit the counterfeit label without the presence of the second image atop the first image, and a trained observer using a light source to highlight the label is able to discern the presence or absence of the second image and thereby distinguish between a label that is counterfeit and a label that is authentic.