The purpose of this master's thesis was to determine the influence of optical properties of various papers with different amounts of optical brightening agents on colour prints. This was made with different printing techniques, electrophotography and an inkjet printer. The research also wanted to determine to what extent the UV inkjet technology would influence the print quality between the most yellowish paper and the white paper. Since whiteness of the paper has a significant influence on the final print, the research was focused mainly on the deviations in measurements of reflectance. The latter was measured by the spectrophotometer with a plane and spherical geometry Our main objective was to determine which paper would be the most suitable for high quality prints. In order to achieve this objective, the analysis of basic properties on papers was conducted, as well as optical properties. Whiteness was calculated according to the standard ISO 11475:2017. On prints of colour checker, CIE L*a*b* values with spectrophotometer i1 Pro 2 were measured and then colour differences were calculated. Research results showed that the reflectance measured with a spectrophotometer with spherical geometry was deviated only for those papers with higher level of whiteness. The lowest level of whiteness was determined to be on the Goričane paper, while the highest one was determined to be on the Navigator. Prints made with an inkjet printer were shown to be highly unsaturated compared to those made by electrophotography, while UV inkjet technology was determined to be the one that enabled even more quality prints. Colour differences between prints made on paper with the lowest level of whiteness and the one with the highest level were obvious. Therefore, it was concluded that the Navigator paper would enable the most saturated high quality contrast prints.
|
