ICC Based Color Image Replication Technology

In the desktop publishing process, copying of color images needs to undergo various stages of image acquisition, processing and processing, color separation, and printing. In each copying stage, the color information will be represented according to the color rendering principle and color description characteristics of the currently used device. For example, digital cameras used as one of color image tools and computers and displays used in processing images use RGB color space to express colors, but colors having the same three primary color components may appear on different digital cameras and displays. Different visual effects. Similarly, color printers and printers work according to the CMYK color space, and there is a color difference in the final prints obtained using different color printers and printers using the same color information. Therefore, in the process of obtaining color images from copying to copying, in addition to undergoing the conversion of the color space, when passing between different devices, deviations may occur due to differences in the specific equipment used, thereby increasing the complexity of the entire copying process. Degree and technical requirements.

This article will use color digital printing as an example to introduce color image replication technology based on ICC. By using color management technology to control the color reproduction on various devices and media in the production system, the entire color reproduction process is automated to ensure that the final The copy can better reproduce the original color.

First, the requirements of the color management system

Using ICC-based color image replication technology, in addition to the usual input devices (including scanners and professional-grade digital cameras), output devices (which can be printers, imagesetters, platesetters, printers, etc.), operating systems And related desktop publishing applications, we must first establish a complete color management system.

A complete color management system should include the profile, profile creation software and standard profiling targets required to create the profile, color management model (CMM), profile file connection space (PCS), and application software interface ( API).

The characteristic file includes the input device characteristic file, the display device characteristic file and the output device characteristic file, and the creation of the device characteristic file requires the characteristic file creation software and the corresponding standard detection object. There are a variety of profile creation software on the market today, such as Kodak ColorFlow ProfileEditor, GretagMacbeth ProfileMaker, and Monaco Profiler software.

The standard test objects required to create a profile include: the objects required to obtain the scanner profile, such as the Kodak IT8.7/1 or /2 standard color chip; the objects required to obtain the digital camera profile, such as GretagMacbeth COIorPatch DC and GretagMacbeth ColorChecker24 standard patch samples; objects required to obtain display profile and output device profile, which are digital files containing multiple color blocks.

Second, the workflow

There are many workflows for color image reproduction based on ICC, and when the image is printed as an independent file or exists as an object in the page file, the specific implementation methods of color management are also different.

According to the application time of the output device characteristic file, it can be divided into the early binding workflow.
(early-binding workflow) and postponement of the Iate-binding workflow. The early binding method converts the color information of all the images from the source color space to the color space of the final output device as early as possible; postponing the binding workflow will try to postpone the conversion of the color information of the image to the color space of the final output device.