Stability of ink-jet prints under influence of light

The aim of this study was to establish whether the use of the desktop ink-jet printing technology, which is more inexpensive and available, is convenient for the preparation of lightfast documents. The influence of the spectral composition of light on paper and print properties was studied, as well as the influence of optical brighteners in paper on fading and the possibility of using archival paper with 30% of post-consumer waste paper fibres for document preparation. The colour samples were printed on three different papers with two different printers, which differed in the ink-jet printing technology and the chemical structure of ink. After determining the paper properties and the colorimetric properties of prints using standard methods, the samples were exposed to xenon light, which simulates daylight in open space and behind window glass. The exposure to xenon light took place under well controlled conditions (spectral composition of light, temperature, relative humidity, exposure time). Based on the spectrophotometric measurements, the colour changes of papers and prints were evaluated on the basis of the CIELAB equation. The research showed that the shortwave radiation proved to be more destructive. The composition of ink and the content of optical brighteners in paper substantially contributed to the latter, as it turned out that the prints on paper which contained optical brightening agents and the prints made with dye-based inks are less stable.