There are many kinds of color devices, such as scanners, digital cameras, monitors, printers, printers, etc., different types of devices, and even devices of the same type and different types, and the ability to express colors is also different. For example, different scanners have different results when scanning the same originals. Different displays have different effects on the same image. Not to mention the difference in the color of printed products caused by the difference in the ink sheets, and the fundamental reason for this difference is. The reason is that each device represents color in its own color space. In other words, the definition of color is device-dependent. For example, it defines a RGB value of a color, which is suitable for a user's certain display, when the same When the value is passed to another monitor, the resulting color effect may change. The reason is that when a color is passed from one device to another, the conversion between color spaces does not perform a good color match.

In order to solve the problem of color space matching, the International Commission on Illumination (CIE) developed the CIE XYZ and CIE Lab specifications. These two color specifications are based on the visual characteristics of the human eye. They are independent of the device and only define the color space. Solve the problem of color management. Color management can be described in Figure 1:

The mode of color management is: from the color of a device's color space, the characteristic file of the device is converted to the mediating color space, and then combined with the characteristic file of the target device, and then converted into the target device color space. In this process, due to the use of a device-independent color space as an intermediary, the color consistency is guaranteed.
From this we can summarize the three elements of color management:
(1) There must be a device-independent color space as an intermediary for color conversion between different devices.
(2) Each device must have a standard specification describing its color characteristics and parameters.
(3) There must be a precise conversion algorithm to achieve the color conversion between different spaces.
In order to standardize the standards of color management, the International Cocor Consortium has established the ICC specification, which is supported by a large number of vendors today. The ICC specification is the result of negotiations among many vendors, and is independent of the device and platform. It describes the method of converting between the device's color space and the mediating color space.
The formulation of the ICC specification is a clear element of color management.
(1) The color space as an intermediary is CIE XYZ or CIE Lab.
(2) The file format that describes the color characteristics of the device is the format defined by the ICC. For CMYK type devices, ICC files usually store multidimensional lookup tables. For RGB type devices, ICC files usually store algorithms that are converted between RGB and CIE Lab.
(3) The color matching algorithm is completed by the manufacturer according to the ICC specification.
To give an example of digital proofing, let's take a look at how color management works. There is a color value suitable for printing (CMYK). According to the ICC profile of the printing environment, we can calculate the visual colorimetric value after printing (CIE Lab). Now according to the ICC profile of the color printer, we can calculate this. (CIE Lab) Another set of color (CMYK) colors needed, this set (CMYK) value and the original (CMYK) value are definitely not the same, but after this color printer output, will have the same visual effect as printing That is, it has the same (CIE Lab) colorimetric value.
The implementation of color management requires a stable color environment. If the result of digital proofing is required to be consistent with the printing result, then the premise is that the printing environment must be stable, and there are some units that do not have strict quality control to do well. If it is required that the display, proofing, and printing be the same as the original, the prerequisite is that the quality of the original must be guaranteed. Foreign countries strictly abide by the principle of color reproduction. If the quality of the finished product is not high due to poor manuscripts, the plate-making company is not responsible and the customer will not pursue it. This is very difficult in China because of the uneven quality of the manuscript. The customer's request to the plate maker is not faithful to the copying of the manuscript, but requires the quality of the manuscript to be further improved by one grade. Under such realistic conditions, the implementation of so-called full color management will not achieve the desired results. Some domestic manufacturers have realized this problem. They are accumulating and analyzing the characteristics of domestic manuscripts. They hope to classify domestic manuscripts and sum up the scanning color separation parameters for each type of manuscript. Under such premise, the entire range of colors will be implemented. Management makes sense.

Traditional Proofing and Digital Proofing

Color management applications generate so-called digital proofing technology in proofing. The goal is to make the results of digital proofing as consistent as possible with the printed results.
The traditional proofing process is as follows:
(1) output film;
(2) System proof board;
(3) mechanical proofing;
(4) If you are not satisfied with the results of the proofing, you will need to make layout adjustments or color adjustments before going back to the first step;
(5) If satisfied, then sign the sample;
(6) printing plate printing, printing on the machine.
The digital proofing process is as follows:
(1) Use digital proofing equipment to output proofs;
(2) If you are not satisfied with the results of the proofing, you need to make layout adjustments or color adjustments, and then return to the first step;
(3) If satisfied, sign the sample;
(4) Output film or plate, printing on the machine.
If we compare these two proofing processes, it is not difficult to get the following conclusions:
(1) Compared with digital proofing, there are many traditional proofing steps, which not only have poor timeliness, but also affect color reproduction due to excessive color transmission.
(2) Some of the key processes of traditional proofing such as aligning and adjusting ink are manual operations with large errors, and the digital proofing operation has a high degree of automation and reduces errors.
(3) The color stability and repeatability of traditional proofing are poor. Different operators will have the same sample proofs, and even the same operator will have different kinds of samples at different times. Digital proofing ensures output stability and repeatability.
(4) Traditional proofing often needs to wait until the work piece can be spelled into a large version before it can be started. Digital proofing is very flexible.
(5) Traditional proofing generally covers a large area, and digital proofing generally takes up less space.
Digital Proofing has so many advantages. Can it quickly replace traditional proofs? No, traditional proofing and digital proofing will coexist for a long time. At present, digital proofing has several problems in applicability, mainly in the following aspects:
(1) difficulty in spot color proofing. Although some digital proofing systems claim to support spot colors, they actually use the CMYK four colors for spot colors, and some digital proofing systems have their own spot colors, but the spot colors are fixed, and the spot colors used in printing are fixed. Not the same. Therefore, digital proofing is generally difficult in terms of spot color performance.
(2) The structure of outlets is different. Popular digital proofing basically uses the dye sublimation technology of dot-tone or dot-less dyeing, which is totally different from the traditional dot-marker's traditional point of view. It remains to be seen whether printer operators can adapt and accept the results of digital proofing.
(3) The degree of color matching between digital proofing and printing has yet to be tested. Although all manufacturers claim that the digital proofing and printing colors are the same, there are still some differences in different degrees. Whether these differences have reached the acceptable range of the industry and different people have different opinions.
When digital proofing was first introduced, many people felt that it was unacceptable. With the passage of time and the gradual maturity of technology, everyone’s ideas have also changed, especially as CTP has gradually evolved from concept to real implementation in the country, resulting in digital proofing. Great promotion. This was verified at the recent Shanghai Digital Proofing and Exchange Seminar. Everyone was interested in participating in the digital proofing product.

Founder color management and digital proofing

Digital proofing requires the interpretation of user-submitted jobs and realistic simulation of printing effects on the printing device. From this mode of operation, we can conclude that the core of digital proofing technology should include two parts: one is the Postscript interpreter technology, and the other is the color Management technology. The former guarantees that the user's work can be properly interpreted, and is exactly the same as the final output of the film and sheet, otherwise, the inconsistency between the results of proofing the RIP and the RIP will cause unnecessary disputes. The latter ensures that the results of the proofing output are consistent with the colors of the printed output.
The RIP kernel of Founder's digital proofing products uses the RIP--the Postscript interpreter kernel of Founder Century RIP. Founder Color Management and Digital Proofing are optional features of the latest RIP version of PSPNT 2.0 from Founder Century RIP. PSPNT2.0 has the following features:
(1) New features supporting Postscript 3;
(2) Good quality, fast speed and high stability;
(3) Widely support Apple platforms and PC platforms, support third-party fonts, and support numerous input file formats and output devices;
(4) Supports the direct dispatching of the TureType word. The batch workstation does not need to download the font to the PS file. Even if the RIP terminal does not have a font, it can use the TrueType font installed in the system to output it and ensure the output.
The color management kernel of Founder's digital proofing products adopts Kodak's latest color management technology. Founder integrates Kodak's latest color management technology in Century RIP 2.0. And recommend to our customers.
Founder's digital proofing products have the following features:
(1) Using Kodak's color management technology to support ICC's international standards;
(2) Closely integrated with Century RIP, using the interpretation kernel of RIP;
(3) Supports personalized color management, which can generate ICC color profile for customer's own color environment;
(4) There are many types of models that can be connected, from popular color ink jets, laser printers to professional Iris printers.
(5) The scope of support is large. It can be supported from 16 to full open. The ability to provide full-page proofing is an important factor in measuring a digital proofing product.