Color box packaging products often have color recovery problems during production, such as neutral gray cast, etc., and then affect the quality of the product, except for the equipment itself and the production personnel
In addition to the problems with the skill level, a key issue is that companies have failed to carry out effective color management and reasonable use of ink.
Color management is to manage people's perception of color, the purpose is to complete the conversion between different colors in the entire image copying process to ensure that the image color from
The appearance shown in the input display to the output can be matched as much as possible, and finally the color and color of the original and the copy are consistent.
Image copying requires multiple stages of image acquisition, processing, color separation, and printing. At each stage, the color information will be colored according to the equipment used at that time.
Affair and color description features are displayed. Inconsistent scanning and display devices will display inconsistent colors for matching originals. Others, using RGB three-color display
The color expression between the four-color printing inks is inconsistent, and the inconsistent use of RGB data into CMYK is also inconsistent. The use of inconsistent paper and oil
Ink, the prints obtained are also different. Therefore, it is necessary to control color restoration on various devices and media in the production system through color management skills.
Content of color management
Establish the color profile of the device (Profile) is the middle of color management, the profile contains the representative color characteristics of each device, such as the characteristic curve of chroma
, The excellent color gamut characteristic curve, etc., the color management system uses these representative color features to complete the matching and conversion of the color space of each device.
For color management, a series of polite operation procedures must be followed to reach the expected consequences. The color management is divided into 3 methods, referred to as "3C"
, Namely calibration (Calibration), characterization (Characterization) and conversion (Conversion).
Calibration: In order to guarantee the invariability, reliability and sustainability of the color information transmission process, it is required to calibrate the input, display and output devices to guarantee them
It is in the form of a standard obligation. Enter the correction for the brightness, contrast, and noisy field of the scanner, etc. In order to guarantee that about the same original, no matter what time is scanned,
Both should be able to obtain the same image data.
By setting the brightness, contrast, color temperature of the display and the gamma value of the entire display system, it can accurately display the color. Output correction and collection printer,
After the calibration of the imagesetter, printing machine and proofer, the characteristics are corrected, so that the device can output according to the standard characteristics at the factory.
Characterization: Recording the corrected characteristics of all equipment is the process of characterization. These feature description files are from the device color space to the standard device-independent color
Space (PCS) bridge for conversion.
Conversion: On the basis of calibrating the system equipment, using equipment description files, using the standard equipment-independent color space as the preamble, to complete the color space between each equipment
Accurate conversion. Because the color gamut of the output device is narrower than the color gamut of the original, scanner, and display, the color gamut needs to be shortened during color conversion, and the color gamut is shortened
In the ICC peace talks, there are four methods: absolute chromaticity method, relative chromaticity method, convex saturation method and sensory method.
Implementation of color management
Slightly speaking, for a packaging and printing company to do a good job of color management, it needs a standard condition light source; high-quality color feature file generation; improve the older generation
Color management system; standard measuring instruments and test equipment; standard color target; standard printing management; standard remote digital proofing color management; standard scan recovery
, Digital camera color management; standard monitor calibration and screen soft proofing. In the specific implementation process of color management, the following aspects should be done: printing carefully
The standardization, standardization, and data-based production management of each process in the whole process are the premise and foundation for the use of ICC color management.
Enterprises should strictly formulate quality standards for fine products, standards for raw and auxiliary materials and equipment such as paper and ink, and standards for measuring instruments and conditional light sources.
Standardize management documents, etc., and require everyone to strictly implement the standards. Monitors, soft proofs, ICC files of printers, various parameters of printing machines, etc. should be standardized, and in the standard and
Quantify within the specification, and summarize all the data that can guarantee the quality through testing means in all places that can be expressed with data. The three are opposed to each other and depend on each other
Deposit, and then guarantee the production of the same high quality and high efficiency.
Pre-press image processing is the foundation and key link of print copy quality. The display should be professional, the scanning of the original and the processing of the digital original should be consistent with the four copy quality
A basic standard (gray balance, tone reproduction, color correction, sharpness enhancement) to point the obligation, and through the specification of the four standard parameters. Scanning the file is complete
Non-adapted manuscript defects are adjusted and artistically processed to make the printed layer more abundant and reach the result of being superior to the manuscript. For remote printing companies, remote digital proofing
The Profile file management can ensure that the digital proofs of the two places have the same color.
Choice of color management system
At that time, there were many color management systems on the market, such as Adobe's Photoshop color management system, Apple's ColorSync color management system, and Kodak's color management.
System etc. Different color management systems have different capabilities for color management of equipment and have their specialties. Therefore, companies must first determine which equipment is required
Seek to get a consistent color for easy selection.
Secondly, it is necessary to determine the self-description file in the color management system and whether it can be supported in the open system to draw the file immediately; if it is a blocked system, it must be
Fang Shu immediately draws the document, how much he needs to determine whether he can afford the cost of the tree immediately draw the document. According to the company's own situation, the system's reliability and equipment support
Comparing and testing various functions such as talent, scalability, compatibility and ease of use. During testing, you can use consistent colorful manuscripts to observe which system is in specific operation.
Under the circumstances, you can get the most consistent results with the original.
Effective color management is a guarantee of the quality of the entire copy, but the final product is obtained through ink. Ink is one of the five basic elements of printing.
Brushing process and quality have the primary impact on results. Accurate and reasonable application and distribution of ink is the key to ensure accurate color recovery.
Ink and ink application
Composition and function of water-based ink: water-based ink is processed by water-soluble resin, high-grade pigments, solvents and additives. The hue depends on the nature of the pigment, the thickness requirements
The pigment has brilliant brilliance, stable coloring power and concealing power, excellent resistance and high divergence. In order to obtain the superior printing suitability of ink and wash, it is often necessary to
The situation uses various types of ink additives to adjust the ink's motility, monotony and viscosity. There are many factors to choose ink quality, and improper use will bring a series of quality problems.
In order to ensure the excellent printing suitability, you should pay attention to analysis when purchasing and using, determine the appearance of the noisy, and make adjustments according to the situation.
In printing, the ink has a certain viscosity is a prerequisite for the normal transmission and transfer of ink. Therefore, the thickness of the high-end ink is controlled to about 20 ± 5 seconds.
, The difference in viscosity will constitute a difference in the shade of the printed color. In the theoretical production process, according to the difference between the load and the temperature, the PH value of the ink on the machine can be adjusted or controlled at 8.0
~ 9.5.
Ink allocation: The first assumption of ink allocation refers to the color of the ink. In the printing of packaging products, the color used in ink is mainly spot color solid flat coating, reaching the vision
And the dual consequences of anti-counterfeiting.
These inconsistent spot colors cannot be overprinted by cyan, magenta, yellow, and black, and often cannot be directly used with original inks, and must be produced by skilled personnel.
The situation was obtained by disproportionate distribution of the original ink.
The color distribution of the ink is based on the subtractive color principle, that is, any color can be disproportionately distributed using the three primary colors, and consider its hue and brightness
And the three basic properties of saturation. When matching colors, the ink used should be selected according to the theoretical printing process, ink layer thickness, printing substrate, etc., and the hue of the ink itself should be considered
, Gloss, coloring power, hiding power and other elements.
Color matching process
Analyze the color of the original: color adjustment is carried out according to the color sample of the original.
Hue and proportion of color ink. The analysis of the original manuscript assumes the use of the method of measuring color by the instrument and connecting the human eye with color. It is simpler to determine the proportion of three primary colors ink by printing chromatography
It can be used to calculate the content of tri-primary ink and white ink according to the percentage of primary color dot area marked in the chromatogram.
Color Matching: Weigh out a small amount of primary color ink for distribution according to the calculated ratio. Pay attention to the comparison between the ink color and the original color from time to time.
The ink is scraped and contrasted on the scraping paper, and it repeats repeatedly until the two colors are exactly the same. When comparing colors, the ink should be uniform, and the thinner the ink layer, the better.
For accuracy, the paper should be the same as the paper used for printing. The adjustment of brightness and saturation is done by adding white ink and black ink. When you need to participate in white and black ink,
Extra attention should be paid to the accuracy of weighing.
After the dispensed ink reaches the original request, the batch ink can be distributed in proportion. The distribution of ink used in a batch of jobs
It is determined by the area, the number of prints, and the amount of loss, and the principle of more is not less.
Record: After the preparation is completed, the information of the ratio of each color ink for ink adjustment, ink adjustment oil, dry oil, ink type, quantity, manufacturer and other information will be published in detail, and it will be later
Use as a reference when mixing ink.
Other pains: When analyzing manuscripts and color comparisons, it is best to use standard light sources or light sources close to daylight, and pay attention to the monotony of the ink film before performing color comparisons.
To increase visual error. Try to use color matching close to the primary color ink or other single color inks. Too many color inks are used for color matching, the worse the brightness and saturation, then
After affecting the printing consequences. Therefore, the fewer the number of inks in color matching, the better. It is better to choose ink products from the same manufacturer.
When making color adjustments, we must fully check the daily printing speed and printing pressure of our equipment, and control the ink viscosity. Inconsistent printing speed and print hue printed under pressure
There will be discrepancies in shades, so the inks distributed at low speeds must be checked again with the original after the printing speed is turned to the normal speed, so as to avoid the existence of color differences, which will cause misunderstanding.
After the ink is adjusted out, it is assumed that there is an error between the color sample printed on the machine and the original and it should be corrected in time. When changing the color, clean the ink fountain and ink roller to avoid cleaning
Unclean and color cast. The spot color ink remaining after printing can still be allocated according to the hue of the new manuscript, but the saturation is often gray, and the residual is retrieved from the ink fountain
The ink may have been emulsified or the printability has changed.
