Color copying and printing problems elaborate packaging

Color copying and printing problems elaborate packaging

Restore Problems box packaging products often appear in the actual production of color, such as neutral gray color cast, thus affecting the quality of products, which in addition to the device itself, there is the technical level of production personnel problem, the key question is not business enabling efficient management and rational use of color ink.

The concept and the need for color management

Color management is the perception of color management is intended to enable conversion between the different colors in the entire image in the process of replication, to ensure that the display color images from input to output in the performance of the appearance as closely as possible, to achieve the final document in harmony with color reproductions.

Copy the image subjected to required image acquisition, processing a plurality of processing stages, color separation, printing and the like, at each stage, will exhibit color information in accordance with currently described characteristics and color rendering principle use of the device. Different scan and display devices have different performance of the same original color. Further, expression of different colors between the RGB three color display Secheng Secheng with the four-color printing inks, coupled with different software applications to convert RGB data into CMYK is also a lack of consistency, the use of different paper and ink, the resulting prints are not the same. Thus, color reproduction must be controlled on the production system through various devices and media color management techniques.

Content color management

Color profile (Profile <br>) is created, the core of color management, file description color characteristics of each device representative characteristic curve as chromaticity, color gamut output characteristic curve, having a color management system uses these representatives color characteristic conversion achieved and matching each device color space.

Color management must be followed during the operation of a series of provisions in order to achieve the desired results. Color management is divided into three steps in principle, simply referred to as "3C", i.e., calibration (Calibration), characterization (Characterization) and Conversion (Conversion).

Calibration: In order to ensure the stability of the color during the information transfer, can be * and sustainability, required input, display and output device calibration, to ensure that they work in the standard state. Input correction scanner or the like comprises luminance, contrast, black and white field correction. For the same original to ensure that, no matter what time scanning, you should be able to get the same image data.

Gamma values by brightness, contrast, and color temperature of the entire display of the display system is set so as to accurately display color. Output correction comprises a correction printer, imagesetters, proofer presses and, after adjustment of its characteristics, so that the apparatus can output in accordance with the standard features of the factory.

Characterization: The characteristics of the apparatus for correcting all recorded, is characteristic of the process. These profiles are characteristic independent color space (PCS) from a bridge device converts the color space standard equipment.

Conversion: On the basis of the calibration device on the system, using the device description file, a standard device-independent color space as the medium, to achieve the correct transitions between the device color space. Since the color gamut than the original output device, a scanner, a narrow color gamut display, it is necessary to compress the color gamut when the color conversion, there are absolute colorimetric color gamut compression method, relative colorimetric method ICC protocol, saturation four methods projection method and sensory methods.

Implementation of color management

Popular terms, for a packaging and printing companies to do color management, the need for a standard ambient light; high-quality color profiles generation software; advanced color management system; standard measurement instruments and testing tools; color standard color target ; standard print management; standard remote digital proofing color management; reduction of the standard scan, digital cameras, color management; standard display screen soft proofing and correction. In a specific embodiment of the color management process, we should do the following aspects: carefully prepare standardized throughout each process printing, standardization, production management data, which is the foundation of the ICC color management applications.

Enterprises should strictly develop intact original auxiliary materials and equipment standards quality standards for fine products, paper, ink and other standard tools and measuring ambient light source, the development of standardized management documents, and asked everyone in strict accordance with the standards. Display, soft proofing, the printer ICC profiles, printing press parameters must be standardized and quantified within the standards and norms, where all data can be expressed by means of tests, summarized the data to ensure quality. Three complementary and interdependent, thus ensuring consistent high quality, high production efficiency.

Prepress image processing technology is the quality of the printed copy foundation and key links. To monitor professional, document scanning and digital document processing should be substantially uniform four standard replication by mass (gray balance, tone reproduction, color correction, sharpness enhancement) to guide the work, and by four standard test specification parameters . Scan files complete, we need the original non-adaptive defects adjustment processing and Art processing, printed materials so that richer level, to achieve better than the original. For remote printing business, remote digital proofing Profile file management, ensuring a consistent two digital color proofs.

Select Color Management System

Currently on the market more color management system, such as Adobe's Photoshop color management system, Apple's ColorSync color management system, Kodak's color management systems. Different color management system is different and has its good part of the color management capabilities of the device, so enterprises must first determine which devices need to get consistent color for selection.

Secondly, we must determine the self-describing file color management system, as well as whether to support the establishment of profiles in open systems; if they are a closed system, you must establish a profile from the factory, so you need to determine whether we can afford to establish profiles the required fee. Should target their own situation, the system can be *, device support can be a variety of performance scalability, compatibility and ease of use were compared and tested and available in the same color original test, which was observed in the specific system under the operating environment, the document can get the most consistent results.

Effective color management is to ensure the overall quality of the copy, but the final product is achieved through the ink. As one of the five elements of printing ink, and has an important influence on the printing process and quality. Ink properly rational use and deployment, is key to ensure accurate color reduction. The use of ink

Composition and properties of ink: The ink is machined from an aqueous water-soluble resin, advanced pigments, solvents and additives. Its hue depending on the nature of the pigment, typically requires pigments with bright color, tinting strength and hiding power suitable, good resistance and high dispersion. To obtain a good printability of the ink, often with a variety of additives to the inks to adjust the flowability, and drying properties of the ink viscosity according to different situations. Many factors determine the quality of the ink, improper use, will bring a series of quality problems, should pay attention to in the purchase and use analysis to determine the merits of its state, and make adjustments according to the situation, in order to ensure its excellent printability .

In printing, the ink having a certain viscosity is necessary for maintaining the normal transmission, the transfer of ink. Thus the ink is generally controlled viscosity grade of about 20 ± 5 seconds, the difference in viscosity will result in different shades of color printing. The actual production process, depending on the composition and temperature of the bearing, PH value of the machine or adjustable ink control between 8.0 and 9.5.

Ink formulation: ink formulation mainly refers to the color of the ink deployment. In packaging printing, color ink used to spot color flat painted mainly to achieve the dual effect of visual and security.

These different spot colors, can not be cyan, magenta, yellow, and black four-color process is made, often can not find direct use of the original ink, according to the production conditions shall art, different proportions of the original ink formulation obtained .

Ink color matching is based on the principle of subtractive color process, i.e. any color using three primary colors can be mixed in different proportions of the deployment, and to consider the three basic properties of hue, lightness and saturation. When used to decide the color of ink, ink itself and consider hue, gloss, color strength, hiding power and other factors in accordance with the actual conditions of the printing process, ink thickness, and other printing substrate.

Color Technology

Analysis of the original color: the color toner is a document for the samples, in order to reduce blindness toning, the color of the document must first be analyzed to determine the need and the ratio of primary color hue ink. Original analysis approach is mainly used color measurement instruments and the human eye than the hue combination. Determined ratio is more simple and practical primary inks, white ink and ink of three primary colors may be calculated based on the percentage content of the primary color dot area marked by printing chromatography chromatogram.

Color: according to the calculated ratio, a small amount of primary color ink to be weighed formulations. Note that the original color ink ongoing comparison, when both the color is close, it is desirable for the transfer ink drawdown drawdown contrast paper, and so forth, until exactly two colors. When the ratio of the color ink should be playing a uniform and ink layer as thin as possible, in order to ensure the accuracy of the color sample hue, the sheet should be the same paper used in printing. Adjust the brightness and saturation is achieved by adding white ink and black ink. When the need to add white, black ink, should pay particular attention to the accuracy of weighing.

After the document reaches the ink out of the deployment requirements, the ratio may be formulated bulk ink. Number of job allocation amount of ink used is usually determined by the type of paper specifications, image size, print run and how much the amount of loss, and the more not less of principle.

Record: upon completion of transfer ink formulation used in the ratio of color ink, varnish, dry oil, ink type, quantity, and other manufacturers detailed registration information, as a reference to facilitate future with ink.

Other Considerations: In analyzing the document, the color ratio, is preferably carried out at or near normal daylight light source, to be noted that while the ink film after drying colorimetrically, in order to reduce the visual error. When the line color close to the primary colors to make use of a single color ink or other inks, color inks using the color too much, brightness and saturation worse, thus affecting the printing results. So when several color ink as possible, with the best choice for a manufacturer of ink products.

To fully understand the factory equipment daily speed and print toner pressure, and control the ink viscosity. Different printing speed and the printing pressure of the hue of the printed product will have different shades, so that a good ink formulations at low printing speed must be open to the normal speed of the document to be checked again, to avoid the presence of color, resulting in waste.

After the ink transferred out of the printing machine if it is found out there is an error with the original color samples must be corrected. To a color change ink fountain, ink roller clean to avoid unclean cleaning generated cast. Spot color inks after printing the remaining, still depending on the hue of the new document to reallocate, but often saturation partial gray, especially excess ink from the ink fountain to retrieve, change is likely to have been emulsified or printability.