Papers by Keyword: Dot Gain

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Authors: Ying Wang, Hao Xue Liu, Min Huang
Abstract: According to the characteristics of ink feeding and printing quality control principles, a new test sheet was designed for qualifying press state and the test results were discussed in this paper. This test sheet was printed under the condition that printing ink volume for different ink zone is identical. Solid density, dot gain and print contrast of different printing ink volume were simulated on a single test sheet, and thus the optimal printing status can be determined quickly. Experiment results show that this method is accessible, economic, and rapid. The optimum solid density values can be got easily for all primary colors on a single test sheet. This method is suit for the adjustment of printing status.
Authors: Li Yi Ma, Tsung Yu Hao
Abstract: To expend the printed color gamut is the most important area for today’s print quality. Conventional wide gamut printing technologies utilize six or seven colors. However, these processes increase the complexity and the cost. Therefore, the four-color wide gamut inks are becoming the major development in Taiwan’s printing industry. This study is focused on the print performance study of the four-color wide gamut inks in the domestic market that are complied with the RoHS regulations. In this study Tung-Ming and K+E wide gamut process inks were tested for their print performance. The press control was to comply ISO12647-2 specifications. The test forms were printed on both type 1 and type 2 papers that specified in ISO12647-2. The normal process ink set was also printed to compare with those wide-gamut color ink sets. The result shows that the both wide-gamut ink sets have reached color gamut larger than the ISO12647-2. In this study shows that the domestic normal process ink set can comply the international standard, and the developing wide gamut ink also reach the standard. However, the color characteristics and printability have to test before using these wide gamut color ink sets. With the optimized process control and color management system, the four-color wide gamut inks can produce the best color result on paper.
Authors: Zhen Cai Qu, Guang Xue Chen, Bao Lin Tang, Shuang Shuang Wen
Abstract: Four kinds of ink-jet papers with different surface characteristics are chosen in this paper, by the ink-jet proofing experiments, the influence of surface characteristics to dot gain is studied, and the law of dot gain with paper surface characteristics is discussed. During the experiment, surface properties including absorbency, gloss, roughness and whiteness are tested firstly; then, the standard wedge of GATF is printed on these papers in the same printing conditions; finally, the dot gain is tested by SpectroEye. After experimental data processing and analysis, dot gain curves of different ink-jet papers are concluded, the law of dot gain with ink-jet paper surface characteristics is summarized. The results show that dot gain is different in different paper, the evaluation of 3# is the best; dot gain is also different with different colors in the same paper, and it is serious in cyan but light in yellow; the biggest dot gain appears in different contrast with different colors, cyan appears near the 65% dot area. The result of this paper offers a certain theoretical reference and practical guidance to the selection, the research and development of ink-jet paper as well as the improvement of ink-jet qualities.
Authors: Chen Fei Zhao, Qing Han
Abstract: Paper is the main print material, whose performance is a factor that effects the printing’s dot gain which is bad to image clarity and color reproduction. In the paper, Yule-Nielsen neugebauer spectral modal is analyzed , and the relation between paper’s spectral reflectance and the printing’s dot gain is discussed. By experiments, the paper’s spectral reflectance is adopted as correction index, which can reduce the dot gain value of the light color patch , and in the same printing conditions the dot gain is effected by the paper’s spectral reflectance, ink’s type, dot area percentage and wavelengths. The research has a certain significance for controlling printing quality and reducing the producing cost.
Authors: Wen Yan Jiang, Xiao Dong Li
Abstract: The influences of screen ruling on printing quality in lithographic printing process based on CTP workflow were investigated by experimental method. Firstly, the test form was output with the screen rulings of 175lpi and 220lpi respectively; then the imaging results of the plates and the prints were compared, and the causes of the differences were analyzed and discussed; at last, corresponding measurements for tone reproduction and process optimization were put forward. Results showed that there were both advantages and disadvantages to increase screen rulings, and the combination of CTP process and finer-than-normal screen rulings would effectively improve the printing quality.
Authors: Pan Pan Yang, Yan Fang Xu, Na Gao, Ya Yuan Zhang
Abstract: In recent years, fluorescent ink, with a unique color performance and the advantages of green non-toxic, fast drying, thin ink, etc., is widely used in packaging printing, security printing, and other fields. Whats more, the luminescent properties and the interaction with paper of fluorescent ink are pained more and more attention. In this experiment, an ultraviolet light source is used to motivate the samples to emit, the fiber spectrophotometer is used to receive the reflected light of the samples in the vertical direction of the samples. The tone rendering curve and dot gain curve are obtained according to the radiation energy data of the sample, the printing indicators of fluorescent ink are obtained by analyzing the reproducing image tone scale and dot expansion characteristics of ink on the paper.
Authors: Xing Yin, Xiao Xiu Hao, Cheng Sun
Abstract: Ink-jet light-box cloth has been widely used in municipal engineering, supermarket, exhibition, hotel and other places, and played an indispensable role of advertising and decoration. There have been no unified parameters and standards for printing quality evaluation of ink-jet light-box cloth. To solve this problem, a group of researches were carried out according to its printability, which selected light-box cloth printed by inkjet. The parameters such as solid density, dot gain, relative contrast of the light-box cloth were tested and analyzed. Based on the results, the printing quality evaluation parameters were put forward. The purpose was to provide reference data for quality evaluation in light-box cloth printing industry.
Authors: Yu Wang, Yu Ying Zhou, Wan Zhang
Abstract: Recently flexography develops faster and faster. The fine degree and the speed for making plate is asked to be higher. Flexographic cyrel digital imager (CDI) can meet the requirements. This article analyzes briefly to the parameters of making plate of CDI. The parameters for affecting the flexographic printing can be ensured. And the correct exposure time is made for making plate. Results show that the quality control is a systematic process. When printing different production, different screen lines, exposure parameters are adopted. By controlling the exposure time, the dot gain can be controlled effectively.
Authors: Qi Wang, Xiao Fan Zhou, Qing Yi
Abstract: Concentric dot is formed by dividing round AM dot into thin concentric rings, which has not only the shape characteristic of AM and FM dots, but also the features and advantages of the two dots. The Concentric Screening is a new halftone screening technology which breaks through the traditional model of reproduction image information by solid dot. To use concentric screening technology in offset printing, the first step is running single color print test to determine concentric screening parameters for the given printing condition. which is unique to concentric screening compare with solid dot printing. Through analyzing and evaluating the printing characteristics of single color print test, the paper provides the method to determine screening parameters such as screening rulings、CTP precision、the width of Ring and Space; Designing and running the four color test based on the first step is aimed to study the reproduction characteristic of concentric dot about gamut、definition、chroma, tone, compared with solid dot. The research shows that the parameters of concentric screening should be determined according to the specific production condition in offset printing. Concentric screening can obtain high saturation and present large color gamut. Also, concentric screening is suitable for high-quality products, which can accept high screen rulings and high-definition. This paper contains experimental study on the correlation between concentric screening parameters and color reproduction. The basis for evaluating concentric screening parameters is offered, and a comprehensive evaluation of its reproduction characteristics is done. This study provides a theoretical basis for the application of the concentric screening technology in offset printing.
Authors: Zhi Jie Li, Ye Chi Pang, Ting Liang Chu
Abstract: This paper proposes an ceaseless compensation method for dot gain based on output characters in printing process, solving the problem of color variation in press controlling, and on the other hand, avoiding wastes made by plate-making and press equipment correction. This control method has a positive function for the working efficiency and technology improvement.
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