| Abstract: | CONCLUSION. The aim of the work was evaluation and comparison of colourfastness of records (cyan, magenta, yellow, black) printed in ink-jet and laser printers on three types of papers artificially aged by different types of light sources. Water and solvents resistance (ethyl alcohol) was evaluated as well. The biggest changes of colour difference were recorded for records and colours aged by the sunlight and UV radiation (middle pressure Hg discharge lamp with luminifor). The significant influence of paper type was observed for colour records made by ink-jet printers. Changes of colour difference for records by the influence of light showed that Jet paper was more suitable for that purpose and observed colour changes were smaller than changes on other papers. However, water and ethyl alcohol resistance of colours printed on Jet paper was lesser than that one on Brilliant paper. Optical density evaluation of colours caused by light ageing showed smaller changes also for Jet paper printed records. Different paper supports had no significant influence on changes of records printed on laser printers. The biggest changes of colour difference were recorded for magenta from ink-jet printers and cyan from laser printers. On the basis of obtained results it can be stated that for colours from ink-jet printers their colour-fastness increased in the following order: magenta < < cyan < yellow < black. The colourfastness ofcolours from laser printers increased in the following order: cyan < magenta < < yellow < black. These orders were not recorded for all combinations of tested samples and light ageing types, however they occurred the most frequently in our experiments. The highest permanence and colourfastness showed black colours from laser printers as well as black colour from the printer Hewlett Packard 920c. Very significant change of colour difference was recorded for cyan colour; it was recorded for all samples printed in both ink-jet and laser printers for all types of light ageing. Only ink-jet printer Hewlett Packard 920c black colour is comparable by its colourfastness, water and ethyl alcohol resistance to tested laser colours. Among tested laser printers colours the black one is the most permanent; other colours-cyan, magenta, yellow-showed more or less the same colourfastness as tested ink-jet printers colours. It can be thus stated that colour records printed by laser printers are comparable by their colourfastness to ink-jet colour records. However, this colourfastness as for laser printers and ink-jet printers as well-can 5c significantly influenced by colour pigment used for their preparation. |
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