engleski

Colorimetric Changes Caused by UV Varnishing

This paper examines the influence of UV LED varnish on color change of varnished substrates. Industrially manufactured dyed papers in 8 different colors (green, red, blue, cyan, yellow, brown, black and light yellow) were UV varnished on Roland VersaUV LEC-300 printing machine in UV LED Inkjet printing technique. Each sample of dyed papers was varnished in four different surface coverage in half-ton values of 20%, 40%, 60% and 80%. Varnished papers were submitted to colorimetric analyses using X-Rite eXact spectrophotometer. From the obtained L*a*b* values, the difference in coloration (ΔE2000) was calculated by CIE Lab ΔE2000 equation. The results of the colorimetric analyses were presented in the form of three-dimensional CIE Lab diagrams showing the color changes in brightness and chromaticity. Color change ΔE2000< 1 is considered visually unnoticeable in contrast to color change ΔE2000> 1 that is visually noticeable. Above the color change, some samples showed significant change in chromaticity.

color change, UV varnish, half-ton value, dyed papers.

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