A Raman Spectral Area Scanning Method to Identify the Sequences of Crossed Writings and Seal Stamps

In the field of document identification, it is always challenging to determine the printing sequences of crossed writings and seal stamps, which can serve as important evidence in litigation. Some common methods to determine the intersection sequence are expensive, destructive, cumbersome, and time-consuming. In this study, we provide several new potential ideas to help solve those problems by using the Raman spectral area scanning method to identify the intersection sequence (printing order) quickly and nondestructively. The results show that for red or blue seal inks, Raman spectroscopy can be used for good verification and as a supplementary method in determining the intersection sequence of writings and seal stamps. It is also effective for pigments analysis and can powerfully complement other analytical methods.