Differentiating Printing Methods Through Physical and Chemical Analyses

Author: Ana Sousa, Materials Engineering and Science Program

Mentor: Dr. Jon Kellar, Department of Materials and Metallurgical Engineering

Mentor: Dr. Grant Crawford, Department of Materials and Metallurgical Engineering

Over the decades, the trade of counterfeit goods has increased, generating revenue losses globally. This has been enabled by advancements in low-cost digital printing methods that are an asset for counterfeit production methods. Each printing method produces characteristic fingerprint features that can be used to authenticate documents and goods.

During the first phase of this research, chemical and physical analyses were performed on printed documents and ink samples for three types of printing methods: inkjet, laserjet, and offset lithography. The results confirmed that it is possible to identify the printing method used by its unique features.

The physical analysis revealed that laserjet prints have a higher image quality, sharper letter edge, glossier appearance on the ink area, thicker ink layer, and the color laserjet printers presented color tracking dots. The inkjet prints presented a lower quality print, random dot pattern, presence of satellite drops, rough edges, and lack of ink in some areas. The offset prints have a sawn edge, did not present satellite drops, did not have a dot pattern, and did not present a significant ink layer. Chemical analysis showed that it was possible to identify distinct components in the ink formulation that can help to differentiate the printing methods. Those components were later confirmed by comparing the collected data with the material safety data sheet.

The obtained knowledge from each printing method and ink characteristics was then used to authenticate suspicious goods. The packages were physically analyzed and their content was chemically examined, and all this data were then compared to authenticate the items. It was possible to identify differences in the product packages and some differences in the formulation of the products. It was shown by the research that it is possible to authenticate different types of goods using the presented analytical approaches.