Reflectance Spectroscopy of Colored Overprints

This paper describes a new methodology for analyzing overprinted stamps. This methodology is based on two procedures. The first performs precise measurements of the dimensions of overprints and a statistical analysis of the minor variations present among them. The second performs a colorimetric analysis of the ink used for printing the overprints. The goal is to determine if these methods can differentiate between overprints made by different printers and if they can allow rapid identification of counterfeit overprints. A set of overprinted stamps from post–World War I Hungary was selected for testing samples. These stamps had many varieties, were produced by two different print shops, and were often counterfeited. After describing the different scientific testing performed, this paper outlines general procedures that may be used by other researchers.