RGB Analysis for Forensic Discrimination of Blue Fountain Pen Inks

This article intends to present a novel and rapid technique for distinguishing inks on disputed papers. The data was acquired by developing specialised image analysis software to assess thin-layer chromatograms (TLC-IA). This study marks Turkey's inaugural application of TLC-IA to analyse fountain pen inks, employing RGB profiles for ink differentiation. This work represents the inaugural investigation into fountain pen inks, employing TLC-IA with RGB analysis for ink differentiation. The ink spot was removed from the document with methanol and isolated by thin-layer chromatography utilising a plastic sheet coated with silica gel 60, devoid of fluorescent indicator, employing a mobile phase composed of ethyl acetate, ethanol, and water in a ratio of 70:35:30 (v/v/v). A novel software was developed to differentiate fountain pen inks based on the intensity profiles of red, green, and blue (RGB) attributes. Subsequently, following the development of the chromatogram, the chromatograms were digitised using a standard office scanner, and the intensity profiles of RGB attributes along the development line of each sample were generated and analysed with bespoke software. The RGB profiles of fountain pen inks from different manufacturers exhibited markedly varied patterns in most instances. This pioneering work in Turkey facilitates the forensic utilisation of TLC-IA for ink analysis, notably focussing on fountain pen inks for the first time.