GMG Colorproof and EFI colorproof Ultimate PK!

This article is the experience and comparison of a certain netizen in a printing forum about the current two most popular digital proofing software in use, and the customer reprints it for readers' reference.

Test Platform: Epson 9800 Printer

Target value: ECI2002R color target printed by user's printing factory 10um frequency modulation network uses lino/scan spectrophotometer to generate target Lab's TXT document through Profilemaker5 measurement. The user's company's ICC color gamut is wider than conventional offset color gamut, so that Can demonstrate the proofing capabilities of the two proofing software.

Spectrophotometer: Eyeone with UV

Paper: ezcolor517

First Round of PK: Initial Linearization

Maximum Ink Limits: GMG: Visual Inspection; EFI: Auto Measure Mono Channel Ink Limits: GMG: No; EFI: Auto Measure Mono Channel Linearization: GMG: No; EFI: Automatic Measurement of Initial Linearization Results Saved: Closed MX3; EFI: closed linearization file. Epl
Printer Profile: GMG: Closed MX3; Efi: Open ICC File

Use process: GMG does not provide paper linearization process, but provides a universal paper linear MX3, then prints a color image of its own printer, and finally generates a new printer feature file MX3 based on the original linear MX3. Can be used for future printer calibration, this process plus wait time is completed in about 1 hour or so, the netizens use this MX3 to print an IT8.73 color target to generate a characteristic ICC for the standard color gamut comparison of the two software.

EFI provides an automated linearization process and generates printer features ICC. The whole process is a fooling process. The entire process takes 2 hours. Since GMG does not provide a linearization tool, this process is missing, so it takes time for GMG to Less than half the time, but the netizen once used a third-party linearization tool and manually adjusted the net friend for 4 hours to complete GMG's basic linear MX3.

After the basic linearization of EFI, EFI can get the best color gamut of 9800 on ezcolor517 paper. The entire color gamut basically contains the color space of the printer, and the color space coverage is 99.8%. The GMG printer's color gamut is smaller than the printer's color gamut in some red areas. This affects the accuracy of the simulation in the later color space conversion. The GMG's color space coverage is 98. 2%.
This round wins EFI

Pk second round: input of simulation target file

GMG input simulation target value must be generated by another module software - colorproof profiler editor to enable the colorproof software to print the simulation output. The colorproof profiler editor must be purchased separately, which means that if you do not buy this software, you cannot easily replace the simulation. Goal value, you can only change your target value or print to GMG to generate Mx4 and let you proof.

EFI is different. It uses a convenient target value setting. It is not only free to set any target value of CMYK (source feature curve called in EFI), (of course you need to generate ICC), but also can use RGB color gamut as your source feature. Values, but also input grayscale images, high-fidelity multicolor images, as long as the source feature color space EFI input these images can immediately enter the proof.

So convenient, no doubt EFI wins!

PK third round: proofing process

Both softwares provide customers with proofing calibration procedures. GMG completes the MX4 editing software: the MX4 software color proof profiler editor. After the proofing software colorproof input MX4 and the printer characteristics file MX3, the printer prints several simulations. At this time, you can let the software print ECI2002r color target and measure the actual lab value of the print result in the colorproof profiler editor. The software can count the comparison result with the target value and re-correct the printer output value according to the result to generate a new round of MX4. Go back to proofing software colorproof to reprint the color target of ECI2002R, and adjust the actual value by adjusting it until two values: the target and the actual color value have a satisfactory result: usually this result can be expressed by the average DE: General 3-4 The next cycle allows the DE value to be <1.

The calibration of EFI is also done in another module software called color manager. This module has many functions, generates linearity, and the printer's characteristic curve is also used to generate the characteristic ICC of other output devices such as printing presses. The paper overview optimization function is to do the output cycle calibration of the printer. Unlike the GMG, the calibration can be performed only on the printer profile, or it can be generated separately for the main program to call, so that after the calibration is completed Does not change the contents of the source properties file and the contents of the printer's properties file. This is a good design! Behind everyone will understand where it is! The calibration process is similar to that of the GMG. EFI also has a choice of color target documents for calibration. ECI2002R can be used. If you are in trouble, you can select IT8 with fewer color patches. 73. This round of the user still judged the EFI victory!

Round 4 of PK: Comparison of Proofing Result Data

The results of the two proofing data comparisons are all satisfactory. The reason that the maximum color difference EFI is better than the GMG is the benefit brought by the precise paper linearization in front, and the largest color difference is often caused by the target color gamut exceeding the printer's range. , And the average color difference GMG is better than EFI fully embodies the biggest selling point of GMG: circular color correction. This round two draws! Ha ha

PK Round 5: Manual Adjustment

A good digital proofing software depends on the data sometimes does not reflect the accuracy of the proofing. The human eye has different sensitivity to the color. Therefore, the test of the same instrument must be discerned by the human eye.

The manual adjustment of GMG is powerful! Although the adjustment interface is not very well done, the adjustment methods provided are as humanistic as possible. Both manual and manual adjustments are of course based on human perspectives, because digital proofing is important for color simulation. , It is used to simulate other output pigments so the adjustment should also be for the color, first GMG provides six basic colors: monochrome C, M, Y, K, R, G, B plus one gray balance CMY To adjust, for example, if you find that the simulated C ink color is inaccurate, and the target color is lacking in magenta, it doesn't matter that you only need to subtract 2-3 points from the c color column in the 0% black column. What's more powerful is that all the colors related to C in the entire system will be adjusted automatically. GMG can easily adjust the hue at each color level of a single black plate! EFI offers a color adjustment scheme in the workflow, but it feels like it's drawing, not adjusting the color! To know that the color adjustment of the digital proofing is to let the printer simulate the color of other printing presses, not to let you print pictures more beautiful! I think this color adjustment is not worth mentioning.

There is also a place where you can manually adjust the color: there is a manual linear adjustment in Color manage. In other words, when you see that the single black or other six basic colors simulated by the proofing are inaccurate, it seems to be powerless in EFI! Fortunately, the function of automatic cycle correction is more powerful, and the result of automatic correction is also satisfactory. You can only accept the judgment of the machine's data and you cannot basically adjust it manually.

This PK is no doubt that GMG has led a lot!

PK Round 6: Printer Self-Calibration

Any printing device will be different from the standard state over time. A good proofing software should see this and have corresponding measures.

In GMG, there is a printer from the user calibration wizard, guiding the user to do a good job of the printer calibration, restore the standard state, this standard state is the initial state of the printer's MX3, so the GMG printer calibration is actually calibrated to the Mx3 The wizard lets you set the average DE and maximum DE to start printing a standard color target. After you measure the input software, it will automatically adjust, and then use the adjusted MX3 to print the color target again. This loop knows the color of the printer. Back to the original MX3 color! This feature is a major feature of the GMG, not only for the printer's own calibration, but also to use another printer to simulate the printer's mx3, then use the same MX4 to print the same proofing color!

Looking at EFI again, there seems to be no clear printer calibration function in EFI, but the user has found a printer's initial linearization readjustment function in the Color manage module. This interface allows you to select the initial linearization curve to be started. Then the printer will print a gradient of a few colors. After it has dried, it will be tested in the software. Even if it is completed, the user thinks this should be the original linearity of the printer. It is a correction process of the printer. How do you still do not know, because the user's EFI has just tried, not so fast changes, but it can not be recycled, the effect is not necessarily good.

This round is again GMG win!

The new version of the two proofing softwares should bring good prospects to the customers, just as a one-on-one simulation (a set of curves or one-time adjustment for a target color space simulation) digital proofing software, GMG's final results And powerful adjustment function is still unparalleled, it allows its color simulation and adjustment to bring unlimited color possibilities for customers!

The strength of EFI is that it not only provides the function of digital proofing, but also a powerful color management tool. It not only provides customers with the simulation of the space of CMYK--->CMYK but also provides customers with accurate conversion of arbitrary color space. Adding simulation, its color simulation function of one-to-many (one adjustment or one set of curves can be simulated for various color spaces) is not available in GMG.

It should be said that GMG is more suitable for digital proofing applications in printing plants, and EFI is more suitable for digital proofing applications with prepress companies. The former is aimed at one goal, while the latter can provide different users with different digital proofing color standards!

Source: Chinese Printing Community