Spot colors are widely used in commercial, product, or packaging printing to obtain a colorful appearance. With the combination of the right software, inks, and media, an ink jet printer can be treated as a digital proofer for spot color printing, providing significant time and cost savings compared to conventional procedures for jobs approval for printing technologies with master image carrier, such as rotogravure, flexography, or offset lithography. An Epson StylusPro 4000 digital printer combined with commercially available raster imaging processors (RIPs) and its own printer drivers were tested and compared. Custom ICC profiles were generated for each print combination, using the gravure production substrate and a manufacturer recommended proofing paper (Epson premium semimatte photopaper). Certain popular Pantone colors and a set of custom spot colors used in gravure decorative laminates industry was investigated and the quality of spot color reproduction was evaluated in terms of the color difference (ΔE*ab) in L*a*b color space. The results show that all tested print combinations have higher ΔE*ab values in highly saturated spot colors, regardless of which printer control software is used. Digital printers employing extended color sets, such as Pantone Hexachrome might be required to reproduce these highly saturated colors. The results also suggested that usage of third party RIP software results in better spot color reproduction. Users can proof spot colors printing via RIPs, if good color matching is considered crucial.
Alexandra Pekarovicova, Yu-Ju Wu, Paul Fleming, "Quality Analysis of Gravure Spot Color Reproduction with an Ink Jet Printer" in Journal of Imaging Science and Technology, 2008, pp 60501-1 - 60501-9, https://doi.org/10.2352/J.ImagingSci.Technol.(2008)52:6(060501)