Green Printing: Colorimetric and Densitometric Analysis of Solvent-based and Vegetable Oil-based Inks of Multicolor Offset Printing

The purpose of this study was to determine the differences in the measurable print attributes (Print Contrast and Dot Gain) and color gamut of solvent-based (SB) inks vs. vegetable oil-based (VO) inks of multicolor offset printing. The literature review revealed a lack of published research on this subject. VO inks tend to perform (color reproduction) better than petroleum inks; in recent years many printers have come to prefer using VO inks. This research adopted an experimental research method. The experiment was conducted in a computer to plate (CTP) based workflow. During the printing, once the density values met the standard (GRACoL) ink density values, the press was run continuously without operator interference and 1,000 sheets were printed, from which 278 were randomly selected for colorimetric and densitometric analysis. The color gamuts of both inks were derived by using colorimetric data. The comparison of SB inks to VO inks led to the conclusion that the latter provides a greater color gamut. VO inks offer greater color perception in printed images. The densitometric findings make it difficult to draw conclusions about print contrast, as each of the inks had statistically significant higher levels of print contrast for two of the four ink colors. Further study is needed to control the variables.