Dejana Đorđević, Aleš Hladnik, Andrej Javoršek

Abstract
Unlike human visual system, image-capturing devices, such as scanners and digital cameras, are unable to accommodate to different light sources. As a consequence, in color acquisition, display and rendering processes a number of chromatic adaptation transforms (CATs) are being used. In our study, a comparison among 15 models consisting of five CATs - Bradford, von Kries, XYZ Scaling, CMCCAT97 and CMCCAT00 - and three illuminant source pairs - D50-A, D50-D65 and D65-A - was made using 8190 color patches. Results showed that colour differences obtained with the Bradford method were the lowest regardless of the implemented illuminant source pair.

Keywords: Chromatic adaptation models, Color differences, Principal components analysis
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Vicente de Garcia, Jesús Inarejos, Susana Otero, Esther Perales and Francisco Martínez-Verdú

Abstract
Colour reproduction is based on the ability to communicate colour information accurately. The different instrument manufacturers, models and conditions result in difficult colour communication due to the loose or inexistent inter-instrumental agreement between them.

With this study we have tried to develop an application to correct colour instruments by software by applying multi-dimensional polynomial transformations between pairs of instruments. This application will filter one spectrophotometer measurement, and apply a correcting factor to emulate the colorimetric response of any other spectrophotometer.

Keywords: Colorimetry, Spectrophotometer, Measurement.
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Alexandra Pekarovicova, Veronika Chovancova-Lovell, Sangmeshwar. L. Sangmule, Paul D. Fleming, Yu Ju Wu, Bill Guillot

Abstract
Spot colors are widely used in commercial, product or packaging printing to obtain a colorful appearance. In this work, we focused on spot color matching and gravure printing of decorative paper laminates. For proofing of spot colors, SmartColourTM iVue software was used. The iVue software enabled us to predict how the press job that was run on a low basis weight substrate will look like on a different substrate, in this case solid bleached sulfate board, based on the previously measured and proofed ink systems that are saved in Sun Chemical’s Global Shade Library. The library is accessed via the iVue software and gives the way of choosing and implementing various ink systems on diverse substrates printed at different press conditions.

Two different ink jet printers were evaluated for their ability to cover the color space of the proposed library. The extra inks that are being incorporated into the newer versions of the digital printers allow for better color control and larger coverage of a color space. One of the printers was then used to produce a proof of the design that would be printed on a specific substrate and will be able to match the original press print. The proof was also previewed in the iVue application and compared to the preview of the commercially available prepress design software. The overprint model and the ability to work with the real data and ink settings in iVue produce incomparable better results when previewing the final job just on a calibrated monitor display.

Keywords: Rotogravure, Spot color matching, SmartColour iVue, Digital proofing
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