Study of ink layer by method of attenuated total reflectance spectroscopy

Abstract

Subject of Research. Research results of thickness distribution of an ink layer smeared on a glass surface are presented. The orange ink which is used as a coloring pigment in writing instrument (highlighter) is selected as an object of study. Method. Researches were carried out by the method of attenuated total reflectance (ATR) spectroscopy. The spectral setup fitted up on the basis of monochromator MDR-204 was used in the experiment. The peculiarity of the measurement scheme is the application of high-resolution camera as a radiation detector and information storage as an images package. Researches allowed receiving experimental data in the form of ink ATR spectra array for studied areas of layer surface in a given spectral range. Main Results. The estimation of ink layer thickness was done, that gives the possibility to visualize its distribution over the surface using three-dimensional modeling capabilities. The thickness of the ink layer is not more than 0.12 microns and arithmetic mean of the thickness is 0.06 microns. The local areas are observed in an ink distribution, they have a maximum layer thickness (0.07-0.12 microns) or areas with the ink thickness less then 0.03 microns. Variation of the ink layer thickness between the local areas is smooth. Practical Relevance. The proposed measuring scheme, the sequence of registration and processing of experimental data can be used to study ink distribution within the thickness of a surface layer of other materials, for example, in analysis of signs performed by an ink on paper medium in order to identify them in such areas of science as forensic science and study of art.