As the market continues to improve the quality requirements of color box products, color management has also received more and more attention. However, various color problems are common in current production. High-quality originals cannot be copied well. The quality of non-adapted originals cannot be improved, which makes the original attractiveness of product packaging not fully manifested. At the same time, it increases scrap and cost and reduces the competitiveness of enterprises. The reason is that in addition to the problems in the technical level of equipment and personnel, the key is that the company fails to carry out effective color management.
The need for color management
Color reproduction is the primary task of printing, where color is at the heart of the life and quality control of printing. However, for a long time, the colors between manuscripts, screen display, proofing, and printing have often not reached the same level, resulting in unnecessary disputes.
There are many variables in the production and reproduction process of the color box. The graphic and text need to undergo multiple stages of scanning, processing, color separation and printing. It is not easy to accurately restore the original. At each stage, the color information will be expressed according to the color rendering characteristics of the currently used device, so different scanning and display devices will have different performances for the same original: In addition, the display with RGB color and C, M, Y, K or C, M, Y, K, LC, LM color printing inks have different color expression capabilities: in addition, different application software conversion data also lacks consistency, and prints obtained using different papers and inks are also Different. Different types of equipment, even equipment of the same type and different models, have different performance capabilities.
Therefore, it is necessary to control the color reproduction on various devices and media in the production system by using color management technology to ensure that the final reproduction can better reproduce the original color.
Color management concept
Color management is the correct interpretation and processing of color information, that is, managing people's perception of color. The essence is the process of converting the color data of an image from one color space to another under the premise of minimum color distortion, so as to ensure that the appearance of the color from the input display to the output is matched as much as possible, and finally the original is consistent with the color of the product. .
The color management implementation converts the color in a device color space into a mediation color space in combination with the device's property file, and then converts it into the target device color space in combination with the target device's property file. The use of a device-independent color space as an intermediary ensures color consistency. According to this implementation process, three elements of color management are obtained:
The device-independent color space acts as an intermediary for color conversion; there must be a standard specification for each device to describe its color characteristics and parameters; there must be an accurate conversion algorithm to achieve color conversion between different spaces.
In order to standardize color management standards, the International Color Consortium (ICC) has developed an ICC specification that clarifies every element of color management: the color space as an intermediary is CIEXYZ or CIELab; the file format describing the color characteristics of the device It is the format specified by ICC; the color matching algorithm is completed by the manufacturer according to the ICC specification.
Color management workflow
Establishing the device's color profile is the core of color management. The description file has representative color features of each device, such as chroma characteristic curve, output color gamut characteristic curve, etc., and the color management system uses these color features. Match and convert the color space of each device.
There are many workflows for ICC-based color image reproduction, and when image is printed as a separate file or as an object in a page file, the specific implementation of color management is different. According to the application time of the output device profile, it can be divided into an Early-binding workflow and a Late-binding workflow. The former converts the color information of all images from the source color space to the color space of the final output device as early as possible; the latter tries to delay the color information conversion of the image to the color space of the final output device.
