As the digitization process goes deeper into every aspect of newspaper printing, the urgency of color management becomes stronger. The printing company of the Henan Daily Press Group has also done some experimental work, but found that it is very difficult to make this job more ideal and the impact factors are numerous. At the time, the factory did not have a whole process. Process equipment, process characteristics, control methods, and data controls are all relatively familiar to the technical personnel. Until the cooperation with Peking University Founder in the implementation of Easy Color Services and the use of digital proofing, color management established a basic framework throughout the entire process. Over the past year, color management has been continuously optimized and played an increasingly important role in the printing of newspapers.
In previous work, when the printing effect of pictures or advertisements was not good, the picture production staff (hereinafter referred to as the graphic staff) and the printing shop pushed each other, and the personnel responsible for quality management suffered from no effective evaluation means. The recurrence of the problem cannot be solved. After using Easy Color Services, we found that Easy Color Service simply means taking color management as the core, controlling the entire printing process flow, and standardizing operations through the training of relevant personnel. The practicality and pertinence of this service project are very strong, and later facts prove that the overall effect is still relatively satisfactory.
The first step in color management - calibration
This step is the commissioning and rectification of all equipment, instruments and work environment in the printing process to ensure the standardization of the entire process and data operation and stable operation. For example, the fluorescent lamps of the graph posts are replaced with the three-color lamps of the standard light source; the printing console is replaced with a standard light source; the display of the sweeping post is replaced with a more professional monitor. At the same time, the scanner correction plays an important role in the correct acquisition of photo manuscript data.
The accuracy of the screen display has an important influence on the image processing effect. In the past, we have always had the phenomenon that the screen display is good, but the printing effect is not ideal. Aside from the stability issues in the printing process, the difference between the display effect and the printing result is also an important reason. In addition, the characteristics of newspaper printing also determine that the processing of the original should conform to human visual habits as much as possible, and the accuracy of the screen display at this time is particularly important. After using BeiDing Founder's digital proofing, we have enhanced the predictability of printing results and found that the problems can be immediately corrected. However, the image processing process is a continuous loss process, and simple repairs cannot fundamentally solve the problem. If the screen display effect can approach the printing effect, many repetitive tasks can be avoided and the work efficiency can be greatly improved.
In the filming and printing section, it is mainly to ensure the quality of the transfer of the film to the plate through the network. In order to make the degree of distortion of the dots in the most ideal range and to take care of the optimal ratio of the ink content of the text and headline words, we set the film density to 3.8±0.1 (based on Agfa film). If the density is low, the quality of the plate will be reduced; on the contrary, the distortion of the intermediate tone and the increase of the film fog will be caused.
The second step of color management - characteristic test
Of course, the closeness of the color display does not obscure the difference caused by the difference in color space. The pictures used for printing must be converted from RGB mode to CMYK mode, and the color space of the picture four-color mode is determined by the actual printing environment. It is necessary to maximize the ability of the printing machine to restore color and levels while avoiding overcorrection. , and also take into account the different types of pictures in the printing process differences.
Data acquisition in the printing process plays an important role in the color management of the entire process. If there is not a basic understanding of the data in the printing process, then not only the pre-press data processing has no reasonable basis, and the print reproduction cannot be achieved. Stable and consistent. This requires an important job - a print test, which is the basis for forming a color management profile. Based on the related data control project in Photoshop software, we tested the following on our factory's printing press (mainly the German Kobao press): density, gray balance data, minimum and maximum dots, maximum ink volume, and dot gain. Network transfer quality, etc.