Color Proofing is necessary to ensure accurate color reproduction before actual printing. Of late, color proofing systems have greatly improved in terms of their functionality, user-friendliness, and output quality. However, client expectations in terms of the quality of color proofs have also increased as well. The common goal is for color samples that are as close as possible to the actual print output, and this is driving continuous improvements in color proofing technology.

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The Yomiuri Shimbun has added a color management system (CMS) to the equipment used in its color proofing process, such as ink-jet color printers and color proofing monitors. In general, images used in newspapers are divided into two categories: photos carried in news sections, and advertisements. The Yomiuri Shimbun uses automated image optimization for news photos, relying on parameters determined to render the most accurate color possible. Advertisement images are provided by the ad agencies in digital files, which are printed using ink-jet printers to check the color. The digital files are then sent to the printing plants. Before printing on paper, the color is adjusted using color proofing monitors for reference. However, occasionally, the galley proofs provided by the agencies are used instead. The new CMS allows stable, high-quality color printing. However, there still is room for improvement, and so no effort will be spared to provide readers with a uniform print quality throughout the paper.

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In recent years, many printing companies have been struggling to meet customer demand for increasingly higher quality, lower cost, and shorter delivery time. The proofing process more likely to be desired for cost efficiency because the process itself does not directly contribute to profits. Direct digital color proofing (DDCP) is a technique used to directly generate color proofs from digital data. It was introduced over 25 years ago and has since been refined. Many types of devices were developed though, the press type proof is still remaining. This paper describes the characteristics and transition of DDCP from sublimation dye transfer printer to inkjet printing, and so on, and color management problems.

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This article presents a method for cylinder proofing, which was formerly used to create a uniform tone between pages in publication gravures. We also describe the evolution of proof press machines and digital color printers in the period between 1990 and 2010. Further, we report on the latest developments from the European Rotogravure Association (ERA) as well as on the standardization of rotogravure printing by using "PSR v2" for publication gravure and "PaC.Space" for packaging gravure. This article also lists future challenges expected in relation to color proofing in rotogravure printing.

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Nowadays, digitalized workflow is gaining popularity and efficiency is essential. In this digital paradigm, color proofing is gaining increasing importance. However, a problem with color proofing is that the color difference measured by colorimeters does not always match the visual color difference. To address this problem, ISO13655 was recently standardized for measuring fluorescent objects under D50 illumination. Our new Virtual Fluorescent Standard technology enables users to easily measure such objects under D50 illumination while accounting for the effect of fluorescence, which is one of the major problems.

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The photographic properties of photopolymerizable composites initiated by the combination of a radical generator and spectral sensitizer were investigated under exposure to light of wavelength 532 nm. The photopolymerizable layer consists of four components: matrix polymer; multifunctional monomer; radical generator; and a dye sensitizer such as cyanine, merocyanine, or indolenine dyes. The dye exhibits an absorption maximum at around 532 nm. Because radical generators such as 2- (p-methoxyphenyl) -4, 6-bis (trichloromethyl) -s-triazine (TCT) and 3, 3'-bis (methoxycarbonyl) -4, 4'-bis (t-butylperoxycarbonyl) benzophenone (BT2) exhibit sensitivity only up to the ultraviolet region, they cannot be directly used as photoinitiators for green-light-sensitive imaging materials. However, the addition of a sensitizing dye extends the spectral sensitivity range of these radical generators toward the longer wavelengths. Upon initiation by BT2 sensitized with cyanine dye, the sensitivity of the photopolymer to light of wavelength 532 nm was 30 μJ⁄cm². The sensitization of the radical generator by the dye involves electron transfer from the excited dye to the radical generator. The holographic properties of photopolymers initiated with the merocyanine⁄BT2 system were evaluated in terms of diffraction efficiency. Real-time diffraction efficiency measurements of transmission holograms were carried out using an optical system equipped with a Nd: YAG laser (532 nm), A hologram with high diffraction efficiency (∼80%) can be formed at 300 mJ⁄cm² exposure.

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