Documents inspection through analysis of microelements in proofs

Abstract

The paper discusses methods for determining the specificity of reproductions (forgeries) of protected documents obtained through various printing techniques. The methods are based on the analysis of printed proofs and measuring of dimensions of characteristic, enlarged details, obtained with a microscope and a digital camera. The software for the analysis is Image Pro Plus. The paper defines methods for measuring the two dimensional parameters: line width and screen dot’s radius. Proofs of reproductions were examined of the vehicle registration card and the FRY passport, obtained with digital printers and offset printing machines, and it was proved that the discussed geometric characteristics may be used as the criteria for detection of forgeries.

U radu su navedene metode za određivanje specifičnosti reprodukcija (falsifikata) zaštićenih dokumenata dobijenih različitim tehnikama štampanja. Metode se baziraju na analizi štampanih otisaka i merenju dimenzija karakterističnih, uvećanih detalja, dobijenih pomoću mikroskopa i digitalne kamere. Kao softver za analizu koristi se program Image Pro Plus. Definisane su metode za merenje dva dimenziona parametra: širine linije i poluprečnika rasterske tačke. Ispitani su otisci reprodukcija saobraćajne dozvole i pasoša SRJ, dobijeni pomoću digitalnih štampača i ofset štamparskih mašina. Pokazano je da se razmatrane geometrijske karakteristike mogu koristiti kao kriterijum za utvrđivanje falsifikata.