Sim Hui Ying, Yvonne, Chin Chin Lim, Chiew Yung Yang, Tan Yan Wen, Crystal
78th Annual Meeting of the American Society of Questioned Document Examiners,
(Virtual) 10th Aug – 14th Aug
Erasable pens with thermochromic inks have been in the market for a long time, and have gained popularity in the last decade. Document examiners have reported on the detection of their use in fraudulent documents. It was reported that the disappearance of an erasable ink at high temperatures, and its re-appearance at low temperatures are attributed to changes in the structure of the ink components at different temperatures. Hence, although the inks are not visible after heat treatment, the ink components that are still present on the surface of the paper facilitate their detection. Several studies have shown that erasable inks can be detected relatively easily using physical and optical techniques such as luminescence, UV, sidelight, ESDA and low temperature exposure. In this study, we further explore the effects of temperature and chemicals on erasable inks. The presentation will discuss the detection of the inks after they have been subjected to repeated hot and cold temperature cycles, as well as chemical treatment.