Igor Zjakić

Identifying a common origin of toner printed counterfeit banknotes by micro-Raman spectroscopy.

This study explores the applicability of micro-Raman spectroscopy as a non-destructive technique for the analysis of color toner printed counterfeits. The main aim of the research paper was to find out whether Raman spectroscopy is a suitable method for establishing the connection between different specimens of counterfeits suspected to be printed with the same toner on the same machine. Specimens of different types of toners printed on different types of paper are analyzed by means of the micro-Raman spectroscopy system with the excitation line at 514.5 nm. For each specimen cyan, magenta and yellow toners are analyzed separately. The yellow toners displayed the most distinctive Raman spectra. The results show that micro-Raman spectroscopy can be successfully applied as a method for the analysis of color toner printed counterfeits, such as banknotes and documents, in order to establish links between more or less different specimens of counterfeits by measuring the properties of a color toner.

Durability Assessment of Functionally Printed Knitted Fabrics for T-Shirts

Knitted shirts are an appropriate carrier for easily readable information, and therefore, in recent years, QR Codes are very often printed on T-shirts. With the purpose of investigating QR Code fastness printed on textiles, in the paper a methodology was proposed for durability assessment of functionally printed knitted fabrics that includes the implementation of long-term care and wearing simulation - which the T-shirts are exposed to over the lifetime. Dimensional changes after multiple washing and drying cycles were determined for non-printed and functionally printed white knitting ; abrasion resistance and tendency to surface pilling after multiple rubbing cycles. The effect of usage simulation on functional prints durability was defined, as well as color fastness, readability and aesthetic properties. It was found that structure of knitted fabrics, their dimensional stability, the number of care and wear cycles performed, the printing technique and size of black modules in QR Code all have an influence on the results obtained.