Vilko Žiljak

Security Methods in the Art and Science using Spectroscopy in the Visual and Near Infrared Range

Near infrared Z values are determined with spectroscopy of colorants, which are used in security charts, printing of documents and banknotes. A new application of security methods in informatics is being observed in this article. The processes of dyeing of fabrics are being controlled by programming twin dyes. Two different mixtures of dyes have been created for the same color. They differ in light absorption only in NIR area. The given, desired difference in their values of light absorption and NIR spectrum has been achieved. Conversely, those are two dyes of different mixture but with the same color parameters in the visual spectrum. The dyes have identical spectra graphs of light absorption in the visual area. The experimental result has been shown in the gallery with infrared pictures and through the design of textile clothes that carries the hidden information. The design with text ―IJNTR – VZ security‖ has been analyzed by forensic light blockages from 400 up to 1000 nm.