Ink that disappears: examination of questioned documents related to Frixion ink in Malaysia

ABSTRACT Frixion ink, which has been introduced into Malaysia's market in recent years, has a special characteristic that it can fade under heat or be rubbed off. Hence there is potential that Frixion ink could be misused repeatedly on the same document for fraudulent purposes. Although such alteration cases have not been reported in Malaysia yet, suitable methods ought to be developed so that local document examiners are prepared beforehand for such situations. The first part of this experiment focuses on deciphering of faded Frixion ink pen strokes while the second part is aimed at differentiating between the faded and fresh Frixion ink without affecting the original state of the documents. Black, blue and red Frixion inks were deposited on foolscap paper and the pen strokes were allowed to fade away through heat or erasure before new entries were overwritten onto the same spot using the same colour of pen. Results showed that the colour of Frixion ink faded completely under both heat and friction from an eraser but the indentation of pen strokes were still observable by treating the samples using Electrostatic Detection Apparatus and the Video Spectral Comparator 6000. Faded blue and black Frixion ink pen strokes could be deciphered clearly under ultraviolet lighting and most preset excitation wavelengths of infrared luminescence while only four wavelength bands of infrared luminescence could be used for the faded red Frixion ink. For overwritten handwriting entries in the second part of the experiment, faded and fresh Frixion ink pen strokes of all colours could be distinguished successfully under ultraviolet lighting. Under infrared luminescence, faded and fresh blue Frixion ink could be differentiated at most preset excitation wavelengths of infrared luminescence while only some of those are useful for black and red Frixion ink. Since this Frixion ink could be abused with criminal intentions due to its unique quality, it is important to raise the awareness of this issue among laboratories and agencies in Malaysia to ensure that the possibility of alteration cases by using Frixion ink was not overlooked.