Earticle

In this paper, an experiment was done where the input device used the linear multiple regression and the sRGB color space to perform a color transformation. The output device used the GOG, GOGO and sRGB for the color transformation. After the input device underwent a color transformation, a 3 ✕ 20 size matrix was used in a linear multiple regression and the scanner's color representation of scanner was better than a digital still camera's color representation. When using the sRGB color space, the original copy and the output copy had a color difference of 11. Therefore it was more efficient to use the linear multiple regression method than using the sRGB color space. After the input device underwent a color transformation, the additivity of the LCD monitor's R, G and B signal value improved and therefore the error in the linear formula transformation decreased. From this change, the LCD monitor with the GOG model applied to the color transformation became better than LCD monitors with other models applied to the color transformation. Also, the color difference varied more than 11 from the original target in CRT and LCD monitors when a sRGB color transformation was done in restricted conditions.

Web offset newspaper prints is the most widely used printing process in domestic printing industry, but there are no industry-wide specifications for press control to assure consistent quality across newspaper printing plants. As newspaper printing becomes more of a commodity and less of an art, it is necessary to develop the print quality specification standard suitable for Korea web offset newspaper printing field. There are a few commonly employed printing standards such as, SNAP (Specification for Non-Heatset Publication) of the US, IFRA(INCA-FIEJ Research Association), J-color (Japan printing machinery association). And there exists KS for domestic standards, however, since it has been directly imported from ISO standards, there are discrepancies in printing materials and media. This paper aims to examine the color reproduction quality of domestic web offset newspaper prints by comparing with foreign standards. Printing experiments on this study have been performed at one of the domestic newspaper printing companies. The color reproduction properties of the web offset newspaper prints are measured by means of densitometry and colorimetry. These measures are evaluated comapratively with the international standards by means of analyzing, the major factors that determine the color reproduction quality of web offset newspaper prints.

Offset printing is one of the well known printing technique of lithographic process and consists of image area and 'non-image area on a flat image carrier. The surface tension of dampening water can be controlled by adding IPA after mixing of raw water and etching solution. The etching solution contains a surfactant for reducing surface energy, a clean agent for non-imaging area, wetting agent for protecting non-imaging area from oil components like ink and also an emulsifying agent for controlling emulsification. In this study, the present situation of dampening water maintenance has examined by collecting dampening water using at domestic companies. The pH related to dampening water, conductivity, contact angle, emulsification curve are measured to define the current situation of dampening water control of each companies and to analyze the relationship among measured properties. In the study most of companies among 16 printing companies tested controlling dampening water through pH value. However, the quality of printing has varied depending upon conductivity, contact angle, IPA content, and emulsification value. The control of dampening water should be carry at the state of the standard when adding proper ratio of etching solution. It would be more effective when pH or conductivity control carries out in parallel with controlling dampening water. Therefore the concept that pH5.5 is correct is based concept. Based on these initial tests it is defined that the standardization of dampening water control is required.

Gravure printing is the most useful printing process than any other engraving printing method. According to the cell which is variable size and depth, ink is transferred substrates. So, the amount of ink from cells has a great effect on the qualities of final printed products. The variables effect on the printability of final products are proportion of the width and length, the rhelogical properties, roll speed etc. However the mechanism of gravure is difficult to study scientifically because of high speed and excessively small size of the cell. To approach the mechanism we experimented the real test by using gravure printability. The condition of variables of IGT is pressure and velocity. By using Polyflow 3. 10. 0 simulation software, we built up the theoretical model under the constant variables. Then, we compared the real test with the simulation results. Therefore, it is studied the mechanism of gravure scientifically and it can be analysed the effect of the variable conditions.

The input and output device requires precise color representation and CMS (Color Management System) because of the increasing number of ways to apply the digital image into electronic publishing. However, there are slight differences in the device dependent color signal among the input and output devices. Also, because of the non-linear conversion of the input signal value to the output signal value, there are color differences between the original copy and the output copy. It seems necessary for device-dependent color information values to change into device-independent color information values. When creating an original copy through electronic publishing, there should be color management with the input and output devices. From the devices' three phases of calibration, characterization and color conversion, the device-dependent color should undergo a color transformation into a device-independent color. In this paper, an experiment was done where the input device used the linear multiple regression and the sRGB color space to perform a color transformation. The output device used the GOG, GOGO and sRGB for the color transformation. After undergoing a color transformation in the input and output devices, the best results were created when the original target underwent a color transformation by the scanner and digital camera input device by the linear multiple regression, and the LCD output device underwent a color transformation by the GOG model.

Recently, the trend in the printing industry includes shorter run lengths and with fast turnaround times. As new markets have made it possible to produce small quantities of high-quality color products at affordable price, the general commercial printing meets the customer's diverse demand by using spot color besides process four colors. Especially, by using spot color for printing the enterprise's logo or specific color, we can see the effect of printing is getting better. With the combination of the right software, ink, media, and device can be treated as a digital proofer for spot color printing, providing significant time and cost savings compared to conventional procedures. The objective of this study is to investigate the quality of spot color proofs printed by ink-jet and dye sublimation proofer using ICC-based color management system. An Epson Stylus Color 3000 ink-jet proofer combined with Best Color Proof XXL RIP was tested for glossy and matte paper. 3M Rainbow dye sublimation proofer was examined using 3M Rainbow controller ver. 4.1 RIP on the manufacturer recommended proofing paper. ICC profiles were generated for each device using ECI 2002 visual target and evaluated for the accuracy of process 4 color reproduction. The test charts consisting of Pantone color 1140 was selected to test the quality of spot color reproduction.

This study starts to find a way out, experiment and apply commercial UV coatings to the cap closures. The cap closures is made form coating and succeeding deformation process. It is coated with several printing layers, printing and over print varnish coating. Then it pressed in three steps of press called 'deep-drawing'. In this study, two kinds of coating was designed and accomplished in the base of the same manufacturing and environment conditions. Consequently, UV curable ink have adequate performance in this experiment (T-bending, Erichsen Test), but it were experienced several damages in this experiments (web-bending, impact test). They were not cured enough to endure the friction and a unique shape of serial cracks were appeared.

In gravure printing, the amount of ink fill into the cells has a great effect on the qualities of final printed products. And printability of final products is determined by every kinds of variables. Ink transfer process is not verified scientifically because gravure cell is small and printing speed is rapid. In order to understand the ink transfer mechanism of conventional gravure, this study is performed using the Computational Fluid Dynamics Evaluation. Flow-3D simulation software is used for considering of Newtonian flow. Among the various factors, this study have dealt with gravure cell types used computer simulation in order to define distinctive features in ink flow in the cell. The results of simulation, it defined the distribution of pressure, speed, stream function, viscosity, shear rate, surface tension during the gravure printing. It is founded out the difficulties and characteristics according to the printing speed and viscosity of Gravure ink.

The CMS(color management system) software was to enable consistent color reproduction from original to reproduction. The CMS was to create RGB monitor and printer characterization profiles and then use the profiles for device independent color transformation. The implemented CMM(color management module) used the CIELAB color space for the profile connection. Various monitor characterization model was evaluated for proper color transformation. To construct output device profile, SLI(sequential linear interpolation) method was used for the color conversion from CMYK device color to device independent CIELAB color space and tetrahedral interpolation method was used for backward transformation. UCR(under color removal) based black generation algorithm was used to construct CIELAB to CMYK LUT(lookup table). When transforming the CIE Lab colour space to CMYK, it was possible to involve the gray revision method regularized in the brightness into colour transformation process and optimize the colour transformation by black generation method based on UCR technique. For soft copy colour proofing, evaluating several monitor specialism methods showed that LUT algorithm was useful. And it was possible to simplify colour gamut mapping by constructing both the look-up table and the colour gamut mapping algorithm to a reference table.