A study of varnish influence on inkjet printing lightfastness

Abstract

Protection of the colour photographs and prints seems as an inevitable step in the preservation of the cultural heritage, because up to 80% of the institutions dealing with cultural heritage have inkjet prints in their collections. Thus it is important to know how they behave when exposed to the environmental conditions. The most harming are light and airborne pollutants. Appling barrier layer, which should protect these prints from ozone and UV light harm, seems like an elegant solution. As the test target was selected i-1 RGB 1.5 target and this target was printed on microporous Ilford Smooth Gloss inkjet paper with dye-based ink set and one pigment ink set. The accelerated ageing test was performed in xenon test chamber Q-Sun with daylight filter on inkjet prints protected by Hahnemühle and Tetenal varnishes. The varnishes were also applied on clear PP films for determination of their spectral change during the light exposure. The reflectance spectra of samples were measured by spectrophotometer i-1. The changes in the gamut volumes were plotted as a function of exposure dose. From this function, fading rate coefficient was determined for each sample. Gamut volumes, fading rate coefficients and gamut visualizations were calculated and made by using VolGa utility.