Several Mainstream Color Management Systems Pre-Press

Adobe's Photoshop color management system is Adobe's most famous image processing software. Photoshop has an irreplaceable position in image processing. At the same time, Adobe also strives to develop Photoshop into a complete color management system. The color management features of Photoshop software are controlled by the Monitor Setup, Printing Inks Setup, and Separation settings.

In order to make the color the user sees on the screen be as close as possible to the color of the output proofs, the user's system must be calibrated first, and the accurate color workflow must begin with the display calibration and display settings. "Monitor Setup" includes two parts of monitor calibration and monitor setup. In the display, the correct selection is made with the display type, phosphor powder, color temperature, etc., so that when the image is converted to the color mode, the correct color conversion can be performed according to the setting of the above parameters.

The basic purpose of printing ink setup is to provide Photoshop with ink, paper, and printing machinery information for final printing. Different papers have different ink absorption and dot gain, different inks have different color rendering properties, and dot gains of different printing methods are also different. So you need to set these parameters in "Printing Inks Setup". After obtaining the basic information from the RGB image data and the display data obtained in "Monitor Setup", the color mode conversion can be performed according to the characteristics of the final printing conditions.

The most important item in the separation is the determination of the black version. In theory, multiple CMYK values ​​can be generated from one RGB value separation, and the final printing effect should be the same. However, due to the ink receiving capacity of different printing papers and the characteristics of different printing machines, the theoretical possibility may not be realized. Therefore, it is necessary to set the type of separation, the amount of black printing, and the percentage of printing total dots.

Apple's ColorSync color management system, ColorSync, is a color management system released by Apple. It adopts the ICC standard and uses the Lab color space as the standard reference space. It is a system-level color management software applied under the Mac operating system. It is an open color management system, users can use ColorSync's Plug-in module to perform color conversion between different color management systems. The ColorSync system consists of three components, an ICC standard color profile, a color matching method (CMM), and an application software interface (API).

The device description file defines the color characteristic information of the device, and through this information, the color range that can be displayed, captured and reproduced by the used device can be obtained. When using ColorSync to create a file, a Profile file is stored in the file so that when processing images with ColorSync profiles on other devices, ColorSync compares the device characteristics of the created image with the characteristics of the display. Color space matching operations to get the best color effect.

The color matching method is the core part of ColorSync, which realizes the conversion of different color spaces. What's more, ColorSync's color conversion mode uses Linotype Hell's high-quality color matching technology. Users can use better color gamut compression methods to handle colors outside of the color space.

Due to the different performance of various application softwares on colors, from the image scanning to the final copying, the same image color will have a different appearance. In order to be able to accurately grasp the colors at work, these application softwares need to perform effective color matching. The color matching method can perform color matching by ColorSync's application software to achieve a consistent purpose.

Kodak's Kodak color management system is a color management system that supports both PC and Mac platforms. Unlike Apple ColorSync and Adobe's Photoshop, Kodak's color management system tends to perform color management in a modular manner, and provides several localized modules that can be combined to form a complete color management system. . And it has a color management function for the Photo CD image input process.

The Kodak color management system generally includes four modules: KPCMS, DCP, PICC and PCS100, which can be used separately or combined into a complete color management system.

The KPCMS module (Kodak Precision Color Management System) provides enough device description files that conform to the ICC standard format. Its input devices include RGB image sources and CMYK image sources, and its output devices include printers and proofers. However, since it cannot edit the device description file itself, it has great limitations.

DCP Module (Device Color Profile Boot Package) is a software package that provides display and output color correction for PhotoCD images. When opening a PhotoCD image, the user is required to select two device description files. The input device description file is a Photo CD device. The description file, the output device description file can be either a monitor description file or a color proofer description file.The PICC module (Precision Input Color Characterization) provides a scanner utility standard program that enhances the DCP functionality.

For advanced image processing and scanning applications, Kodak offers the PCS100 module to speed the color conversion process of Photo CD and Prophoto CD images. With the PCS100 module, direct links between various devices can be generated to skip the intermediate conversion process to the CIE color space, saving time for each conversion and color loss during conversion.