About the screen soft proofing

Question one, the relationship between screen color management and printing process?

Do color management, do a good job in the printing process, because the stability of the printing process directly affects the effect of pre-press color management, because any color management, including digital proofing, monitor calibration, scanner color management, are used in the printing The ICC document, that is to say, in the standard state of the printing press, and in accordance with standard environmental conditions such as temperature, humidity, printing process, pressure, ink and ink balance, printing standard color code, to get printed ICC profile, Then use this profile to do the monitor's color management. Therefore, the standardization of printing plants is very important.

This allows the display to reflect the actual printing effect. Stable post-processes are critical to color management and color management is possible regardless of the equipment's grade. Therefore, the stability of the post process can provide a stable ICC profile. At present, many companies use high-fidelity printing and spot color printing, which puts higher requirements on pre-press color management.

Problem two: In the display color management, multiple curves need to be created, but what kind of criteria and factors should be used to select the appropriate curve?

Display color management requires multiple ICC profiles. The final evaluation of a color management result is based on data. Based on visual inspection, the first comparison to ICC is to see which ICC is better, and the software is used to evaluate the function. The ICC selected the smallest ICC for ΔE. The △E minimum indicates that this ICC file is the best. But whether to choose this ICC will ultimately be based on visual inspection. Sometimes the smallest ICC with △E shows that the visual effect is not necessarily the best. If △E conflicts with visual inspection, it should be based on visual results rather than blindly pursuing △E minimum. Because the customer sign is based on visual inspection, not △E. In principle, due to the different calculation formula of ΔE, the data and the human eye have differences in visual inspection. However, due to the fact that international standards have not yet been established, there are two calculation methods that are similar to the human eye's visual results.

Question 3: Is there any difference between EIZO monitors of different models and production dates and different production sites?

Color matching of EIZO monitors Although different models, different production dates, and different production locations will bring about some differences, the display effect of EIZO series monitors is still very close. For example, the CG series monitors are mainly used for the reproduction of artworks, high-end printing, and screen soft proofing. Therefore, there is no problem for remote soft proofing with different types of monitors in the series. If it is a match between different series, for example, the color performances of L797 and CG19 are very close. Although L797 and L997 have no automatically corrected chips, they are very similar in color performance. Because it can be achieved through software and custom functions, such as every 500K from 4000K to 10000K color temperature, like every gamma from 1.8 to 2.6, including (RGBCMY) 6 colors can be independently tuned to achieve color consistency. However, it may have problems if it is used with other types of LCD screens.

Question 4: Can front-end displays processed through post-processes be simulated?

This problem is not related to the monitor itself. It mainly depends on the ICC profile obtained by the subsequent process. For example, the ICC file obtained by the unlaminated and laminated printed matter is not the same, depending on which one is used as the reference for front-end calibration. Of course, it is also possible to create separate color management profiles for different post-press processing products. In this way, on the front-end display, customers can see what the effect of printed products after printing is. But there is a premise here is the degree of standardization and stability of your printing and finishing processes.

Question 5. In high fidelity, can the monitor accurately or tune out accurate Pantone colors?

From the principle and data, if this Pantone color is within the color gamut of the display, this Pantone color should be displayed. But back to the issues we discussed today, even if the data is very close, the results of human observations do not necessarily meet the data display. When it comes to Pantone color, it often refers to two concepts in actual applications. One is that the customer has Pantone blocks for you to chase, and the other is for customers to tell you that a Pantone value lets you print. This should be treated separately. If it is chasing color blocks, it is not necessary to hold the value. Because the closeness of the numerical value does not necessarily appear in the color, as long as it is based on the customer's visual acceptance. If you are chasing numbers, you must chase the numbers as close as possible. Because Pantone color samples may be discolored due to environmental factors. Therefore, first of all, it must be clear whether the customer is chasing data or proofs. High-end displays can display the vast majority of 1485 colors in high-fidelity prints, and only about 10 can't accurately display them. Like EIZO's CG220, its color gamut is beyond Pantone's range and there is no problem with the display of spot colors. Whether or not the monitor can display spot colors can be measured by the instrument to obtain its displayed Lab value, so as to initially determine whether its color gamut range can cover Pantone colors. Color management should be based on data for high-end color reproduction, and the average value of human eyes should be the confirmation standard. Therefore, in China's high-end level of high-fidelity replication, the instrument's data can only serve as a reference value, and professionals with rich color experience are even more important in fine-tuning color. People's visual gap in the visual inspection is irreparable. At the same time, experts once again emphasized that the standardization of the observation environment has a direct impact on the results of color management.

Sixth, the original European standards that often encountered color in the work of color management, American standards, do we have Chinese standards?

Rainbow Dijet has been cooperating with Apple to develop related color standards. And will continue to study. But merely interfacing with Apple is not enough. At present, well-known printing companies in China are actively cooperating with our research, but there is still a long way to go to reach China's color standards. Because this is not just color management, but a huge system engineering.

Question 7, PDF file color management issues and remote proofing problems.

The core of matching problems in off-site proofing is the problem of duplication and matching of the results of proofing and local printing. Therefore, in the current situation, it is best to use hard proofs. But in the future it is possible to achieve soft proofing of remote screens. The key is whether the customer approves the data copy or the copy of the print result. If the customer accepts data within a certain range and applies the same ICC profile, remote proofing can be achieved.

No matter whether it is hard proofing or soft proofing, the soft proofing of the screen is theoretically and technically feasible. It is nothing more than the proofing implemented in different places. However, the prerequisite for proofing is the acquisition of the original document, that is, the acquisition of the original ICC characteristic document. And whether the environment for obtaining the original ICC file is standard, what the specific information it carries, and then the requirements of the target ICC profile, that is, the effect to be achieved by the human eye. As long as the original characteristic text and the target characteristic file are matched and matched, remote remote proofing can be achieved. Coupled with the adjustment of all output devices in the CIE color space, it is guaranteed to be the actual feeling that our eyes see, and it should be possible to output an accurate color. Remote proofing will be the future trend, whether hard proof or screen proofing. Screen soft proofing is still under development. Domestic printers have already adopted this technology. In the future, printing houses will face more and more issues of printing in different places.

Note: This article is for the reference of the theme of the Color Club organized by the Institute of Printing Academy, which is “Quality Management of Monitors and Screen Soft Proofing”.

Source: Ke Yin Network