Influence of moist-heat accelerated ageing on yellow ElectroInk screen elements

The results from an investigation of the colour characteristic and changes in the size and shape of yellow screen elements of LEP (Liquid Electro-photography Printing) prints exposed to moist-heat ageing are presented. Three sample series are analysed: prints on the non-aged paper, accelerated aged prints and prints on accelerated aged paper. The results showed that prints on the aged recycled paper and on aged fine art paper show greater colour change than aged prints on non-aged paper. The tonal values were influenced by such printing substrates on the yellow reproduction. A decrease in colour differences of prints appears on the aged offset paper used as printing substrate by increasing the screen value in area of 10%-20%. Moist-heat aged prints on offset paper influences the decrease of yellow screen elements, which is not the case for the prints made on recycled paper and those made on fine art paper. Printing on the aged paper results especially in a 30% increased reproduction of the screen elements in darker tones. On all the three paper kinds greater deviations were found along the horizontal length of the screen element in comparison to the vertical diameter length.