Printing color management and printing production optimization

Printing color management and printing production optimization

　　 The optimization of printing production includes: equipment state optimization and production process optimization. Equipment status optimization refers to the adjustment of various equipment in the printing production and the settings of various environmental and material factors that cooperate with the equipment to make the equipment run in a stable and optimal state, and to give full play to the efficiency of the equipment. Production process optimization refers to the greatest degree of reduction and automation of printing production process links. From the perspective of color control, it involves the pre-press and printing process. Figure 2 shows the printed color management process after production optimization.

  1. Equipment status optimization

　　Equipment status optimization is the coordination and unification of the printing environment, printing materials and various hardware devices, which mainly include the optimization of the printing press and the optimization of the prepress equipment. The optimization objects of prepress equipment include scanners, computers, monitors, laser imagesetters, CTPs and digital proofing machines. The optimization method is to stabilize the printing process parameters through digitization and standardization, as follows:

　　1) Standardization and standardization of the printing environment

　　 The printing environment mainly refers to the temperature, humidity, and lighting conditions before printing and the printing workshop. The standardization and standardization of the printing environment should be based on national or international printing industry standards. The temperature and relative humidity of the workshop should be kept in the best condition to minimize static electricity, minimize dust, paper lint and other pollutants on the film, printing plate and equipment, maintain the stability of the paper, and minimize dampening. Problems with plate fluid, printing plate and ink. The standardization of lighting conditions requires the establishment of a standard observation environment. For example, the walls of the workshop should be kept in neutral gray, and the D65 or D50 standard light source and light box should be used to ensure the stability and consistency of the observation of image originals and printed samples.

　　 2) Standardization of printed materials

　　 The standardization of printed materials includes the standardization of material purchase, material testing and performance data file establishment. It is best to implement relevant quality standards (such as the ISO9002 standard system). Printing companies should formulate standards for material selection and purchase, inspect and test raw materials, determine the properties of materials, the compatibility between materials, and the compatibility between materials and equipment, and establish material data files to standardize printed materials manage. The printing materials mainly include: ink, printing plate, blanket, roller, paper and fountain solution, etc.

　　3) Calibration and standardization of display

　　 The requirements for the display in the pre-press environment are relatively high, and the color rendering characteristics of the display are affected by many factors such as the lighting environment and the brightness of the display. The most ideal lighting environment for the display requires thick dark curtains to cover the windows to avoid interference from external light sources and prevent the impact of ambient light on the color perception of human eyes. In addition, the display itself needs to be calibrated before use. Although the display has passed the manufacturer's debugging and calibration before leaving the factory, no two displays are exactly the same, and the color reproduction performance of the display will change over time. The monitor can be calibrated with a screen calibrator. The calibration items mainly include brightness, contrast, Gamma value, fluorescent agent type, etc.

　　4) Calibration and standardization of scanner

　　Most scanners will self-calibrate at startup. Scanners with auto-calibration function will perform self-checking based on a built-in reference. For scanners without automatic calibration function, it must be calibrated. Scanners can generally be calibrated using IT8 color scale.

　　5) Standardization of film output process

　　 The standardization of the film output process is to ensure the quality of the film output. The optimization work should start from the printing press, and then return to the pre-press system and color separation. Printing machine optimization requires standard settings for each part of the printing machine, knowing what problems may occur in printing, evaluating the quality and compatibility of printed materials, and finally determining the optimal working state of the printing machine, and stabilizing this state.

　　 includes the selection of film, the test of film performance, the control of developer temperature and concentration, and the establishment of film output data files. The quality of film output mainly has two factors: film density and linearization control of film recording dots. The density of the film generally requires that the minimum density value is not greater than 0.07, and the maximum density is not less than 3.5. The linearization function of the dots can be set in RIP, the purpose is to ensure that the dots can be correctly recorded on the film.

　　6) Standardization of traditional printing process

　　The standardization of the traditional printing process embodies the concept of plate making with printing as the center of gravity. High-quality, high-efficiency and standardized printing makes a great contribution to improving the overall printing production efficiency. The standardization of the printing process includes: keeping the printing workshop clean and dust-free, the humidity meets the requirements, ensuring the stable performance of the printing machine, mastering the correct exposure and development time, and making good use of various testing tools.

　　7) Standardization of CTP plate making

　　 CTP plate making shortens the printing production cycle and improves the printing efficiency. Compared with the traditional plate making process, CTP has the advantages of high timeliness, good dot quality, and large range of reproducible tone levels. The standardization of ℃TP plate making should refer to the traditional printing process parameters to establish a good digital production environment.

　　 8) Standardization of digital proofing

　　Digital proofing is the process of using digital manuscripts to directly output printed proofs. The main purpose is to realize the customer's proofs. Therefore, printing companies generally use customer satisfaction as the standard for proofing qualifications. But this kind of non-professional subjective evaluation will inevitably lead to many problems. For example, when the printed matter cannot achieve the color effect of the sample, there will be conflicts between the customer and the company. When the printed matter matches the proofs, the company cannot guarantee the quality of the proofs next time because there is no standard for quantitatively measuring the proofs. In order to solve these problems, printing companies must formulate digital proofing standardized documents to standardize digital proofing. The standardization of digital proofing includes choosing a suitable digital printer and supporting paper and ink, collecting data based on printing to realize the color gamut of digital proofing machine simulation printing, and regular inspection and maintenance of the digital proofing system.

　　 9) Standardization of printing presses

　　 The purpose of printing press standardization is to find the best match between the printing press and the printed materials, and to determine the maximum ink density and dot expansion characteristics of the printing press. This process must be completed through a series of tests. The setting of the printing components of the printing machine should be carried out according to the instructions of the printing machine manufacturer, including the setting of the ink roller and water roller, the compression setting of the printing blanket, the correctness of the printing plate and the blanket lining, and the output of the printing machine. The cleaning and lubrication of paper device, the cleaning and lubrication of paper transfer system and delivery device, etc. On this basis, the material and the printing machine performance matching test are carried out to determine the optimal state of the printing machine and make it data.

  2. Production process optimization

　　 mainly includes two aspects: optimizing the ink preset and optimizing the control of the color reproduction process.

　　 (1) Optimize ink presets

　　Ink preset refers to the determination of the ink preset value of the printing press. There are three methods for ink pre-setting: human experience setting, printing plate scanning setting, and printing ink pre-setting data directly from the pre-press link. The accuracy and efficiency of human experience setting mainly depends on the printing production personnel. Data and standardization are more difficult, and the formation of experience takes a long time. The printing plate scanning setting refers to scanning and analyzing the graphic information in the yellow, magenta, cyan, and black printing plates through the printing plate scanner, to obtain the ink preset data, and to save the preset data through the storage device or the network Passed to the printing press control center, and finally reflected on the printing press. Its accuracy and efficiency depend on the accuracy of the printing plate scanner, the speed of scanning and the speed of data transmission. The third method is to directly generate ink preset data from the pre-press link. The system for generating ink preset data is a digital workflow. In the digital workflow, the preset data is transmitted to the printing machine as a PPF (PrintProductionFormat) file through the memory or the network. Control center, and finally reflected on the printing press, as shown in Figure 3. Comparing the three methods, the third method is faster, more stable, easier to achieve data and standardization, and can better optimize the printing production process.

　　 (2) Optimize the control of the color reproduction process

　　 The color reduction process is controlled by real-time collection and analysis of printed images through some online printing quality monitoring systems, and the results are fed back to the pre-press link and the printing console for timely correction. Optimizing the control of the color reproduction process is mainly to establish an effective automatic color reproduction control system, build a communication bridge between prepress and printing, and improve the effective running time of the printing press.