Color Management in the Printing Process (I)

Color management may be faced every day in your production process. It is just the question of how to set the process in the previous process, such as the selection of tools, and the selection of colors. The emphasis we put here is How to easily implement color management for everyone in the entire workflow.

First of all, let's start with an architecture for color management in a printing factory: We actually did an experiment this time. The tools used were:

● Roland 5-color printing machine 700+Pecom from Shanghai Printing Factory

● Agfa's color management system ColorTunePro3.02

● Color Management System PrintOpen 3.0 from Heidelberg

● Agfa's Prepress Process Management System Apogee

● Taiwan Barco Screen and Color Management System

● Agfae Prepress Proofing Equipment Apogee Sherpa43

● Standard light source D65 light box

Under such an architecture, we have a printed color management process.

(1) The most important thing in the entire color management process is the final goal of color management. It is the final printed matter. Therefore, we must first do a Printer Profile (printer's color profile) for this part. Why? To do the Printer Profile first because we hope that our color simulation object is based on the final delivery of the print, first do the Printer Profile so that there is a basis, so in the entire color management process, the printer color profile, must You have to do it first, and then you can go forward and continue to do it, and continue to deduct a parameter that you should get for each process. So the process we did was to use an electronic version of the IT8-7/3 to directly feed the film output machine, print it into a plate or use CTP to make the plate directly, and use a standard printing condition on the printing machine. This printing condition is based on the SID. (Full version of ink density), and DG (dot point expansion) to control, these two parameters must be set in the common factory production of commonly used values, in this setting down to get the printer's color profile, In the IT8-7/3 manuscript, there are 928 color blocks. Using the colorimeter to measure, the color profile of the printer can be obtained.

(b) In addition, we use inkjet proofers to directly make proofing of printing presses in the area of ​​simulating printing presses. In this section, we must first perform a “linear calibration” on the SID and DG parts of inkjet proofers. Let the inkjet proofer conform to the color gamut that our printing machine can print out, and this "linear correction" is based on the previously mentioned value of printing production, otherwise the proof of inkjet proofing may be that the printing press cannot Printed color, after such a process, we can get Proofer Profile (ink-jet color profile)

(C) The screen is a basis for everyone to look at the file, we can use some tools to do the screen color description file, its main structure is the use of LED light, through the filter to receive a different color stimulus value X , Y, Z, produces the screen color description file, records the screen the color recording ability.

To this end, we only made a total of three color profiles, recording the color recording capabilities of three different devices, including printers, inkjet proofers, and screens. After all three parameters are available, a digital proofing process begins.

(d) The so-called digital proofing is the use of raw digital files through inkjet RIP, and this RIP must have the ability to input source files and respond to the device's feature descriptors to the final printout. So the process of digital proofing is that you give it a source, give it a destination, it can use inkjet proofing to simulate the results of the printing; the same inkjet proofer can do, the screen can also be done, as long as the destination will be just It is a color description file of the screen that the inkjet color description file can be replaced, and the result of printing can be predicted on Photshop.

(5) We can also use the browser's interface to directly make a remote proof of the file. The structure is to use the original print file, reduce its DPI number, use the remote screen, open the file, that is, use the browse Interface, but currently only the Mac operating system Internet Explorer can do the color comparison with the ColorSync under the Mac. On the PC, the Windows operating system can't compare colors at present.