Undoubtedly, tri-primary ink printing has developed from original painting to scientific imprinting, from photo-making to full digital printing, and has made great progress. But printers must also improve the variability of raw materials such as inks and substrates that are directly related to the composition of the final printed product. These variabilities, especially those that contain multiple types of substrates, have a great influence on the color balance.
The color imbalance will cause the printed copy to produce an overall color cast. The typical situation is that when the overall color of the print containing neutral gray areas is cast, the characteristics are very obvious. Color imbalances can be produced at multiple stages in printing, regardless of when the image is transferred to another format. For example, when scanning, the conversion from RGB to CMYK and output to the proofer and printing machine (or printer) will cause the color change.
The digital color management system reduces the occurrence of color imbalance in the pre-press part to a greater extent by adjusting the tone values ​​of different devices. However, printing as a whole, color imbalances still prevail, especially paper prints. This article describes the application of three-color color management for gray balance control in printing.
Color transfer
To understand how to control color cast, you must first look at the color delivery system. In characterizing the replication process and the subsequent printing process, two important operators decide the color balance of the entire tonal range of three primary colors printing. One is the printing operator, who decides the control of ink imprinting order, imprinting value, and color density of the three primary colors; the other is the prepress operator, who sets the ink percentage of the imprinting color in the halftone area of ​​printing, such as high-profile and mid-tone setting.
The overall color balance of the printed copy is determined by the strength (density) and color (hue and saturation) of the three primary inks. Only when these printing factors remain stable can the percentage of color dots in the printing be determined. In the printing and color transmission and copying between printing and pre-press, if there is no strict control, the parameter control of the color management system alone cannot guarantee the printing quality. Practice shows that controlling ink density and gray balance through experience is the most important part in color management of halftone color printing.
Gray balance control is not a new concept. Before the computer age, when performing color separations based on photographs, the standard SWOP (Offset Publishing Guide) density was already established. However, several things have changed at present. One is that flexographic printing has occupied an important seat in the three-primary color printing; second, the basic ink primary colors have also changed a lot due to the emergence of new ink pigment technologies. Moreover, digital artwork has already appeared.
At the moment of transition to new technology, although the discussion about gray balance control seems to have no meaning, therefore, to emphasize it, we must work hard to make color management more effective.
The color management system is controlled by printing. On the contrary, the printing control can only be obtained when the substrate color, the ink color of the three primary colors, the ink overprint, and other printing variables are relatively stable and balanced. In fact, the balance of these important parameters will continue to change with changes in printing, such as to match the changing basic materials, inks, and substrates. Pre-press artists have used all the control, color management and measurement systems, but still can not guarantee that they can obtain consistent, balanced halftone products. The reason is that small changes in substrate color, ink opacity, or overprinting have not been discovered by the printer.
Gray balance and three primary colors ink overprint
In printing, the three primary colors of ink are mixed in different proportions to obtain the desired color spectrum tone value. The density and correctness of the three primary colors of ink printed on the substrate have a direct relationship with the printing staff. As a guide for obtaining the correct ink contrast, density balance should be operated in accordance with FIRST (Flexographic Image Reproduction Specifications and Tolerances).
Printing operators can only measure and set ink density within a limited range, which is described in various publication guides such as FIRST and SWOP. But these density ranges can obtain a large range of overprint ink colors, and regardless of whether the ink is pure and transparent, or whether the substrate is pure white. In general, the application of the pre-press color management system that currently exists actually is not ideal for controlling printing colors.
The ink density range according to the instructions can be used for any ink overprinting sequence, namely YMC, YCM, CMY, CYM, MCY or MYC. But does each sequence produce the same color? No.
Even when the solid density is controlled to an absolute value, each overprint sequence will produce different overprint colors of red, green, and blue, because each printing ink formulation has its own different properties, such as ink opacity that affects the coverage rate. Therefore, the surface energy of the ink dried film layer printed first will affect the adhesion characteristics of the wet ink printed later.
Yellow pigments have poor coverage, and magenta and cyan pigments have good coverage. But the surface energy of yellow pigment ink is high.
The first step in color management in printing is to determine the best ink overprint sequence and density balance that can provide a high color rendering range. The GATF Association developed a simple color hexagon color map many years ago to visualize the ratio of different colors. The density meter can display the quality of the color by measuring the hue deviation, gray scale and overprint color and compare it with the three primary colors.
For example, the three corners of the hexagonal color diagram that are not adjacent to each other are the ideal primary ink color (YMC), the other three corners are the overprint composite color (RGB), and the center of the hexagon is the neutral color (white to gray) To black). The greater the color strength of the ink, the closer to the corners, the farther away from the neutral color.
When the actual printing colors and composite colors are distributed in the hexagonal color map, the density, hue difference, and gray value of the three primary colors (CMY) and composite colors (RGB) are displayed. Because the ink is not too ideal, the distributed hexagons (irregular) will not be the same size as the entire ideal hexagon color map, but it can be used for optimal printing. Therefore, using the GAFT method for irregular hexagonal distribution to display the printed three primary colors and composite color information, you can get the best density and overprint sequence.
The color imbalance will cause the printed copy to produce an overall color cast. The typical situation is that when the overall color of the print containing neutral gray areas is cast, the characteristics are very obvious. Color imbalances can be produced at multiple stages in printing, regardless of when the image is transferred to another format. For example, when scanning, the conversion from RGB to CMYK and output to the proofer and printing machine (or printer) will cause the color change.
The digital color management system reduces the occurrence of color imbalance in the pre-press part to a greater extent by adjusting the tone values ​​of different devices. However, printing as a whole, color imbalances still prevail, especially paper prints. This article describes the application of three-color color management for gray balance control in printing.
Color transfer
To understand how to control color cast, you must first look at the color delivery system. In characterizing the replication process and the subsequent printing process, two important operators decide the color balance of the entire tonal range of three primary colors printing. One is the printing operator, who decides the control of ink imprinting order, imprinting value, and color density of the three primary colors; the other is the prepress operator, who sets the ink percentage of the imprinting color in the halftone area of ​​printing, such as high-profile and mid-tone setting.
The overall color balance of the printed copy is determined by the strength (density) and color (hue and saturation) of the three primary inks. Only when these printing factors remain stable can the percentage of color dots in the printing be determined. In the printing and color transmission and copying between printing and pre-press, if there is no strict control, the parameter control of the color management system alone cannot guarantee the printing quality. Practice shows that controlling ink density and gray balance through experience is the most important part in color management of halftone color printing.
Gray balance control is not a new concept. Before the computer age, when performing color separations based on photographs, the standard SWOP (Offset Publishing Guide) density was already established. However, several things have changed at present. One is that flexographic printing has occupied an important seat in the three-primary color printing; second, the basic ink primary colors have also changed a lot due to the emergence of new ink pigment technologies. Moreover, digital artwork has already appeared.
At the moment of transition to new technology, although the discussion about gray balance control seems to have no meaning, therefore, to emphasize it, we must work hard to make color management more effective.
The color management system is controlled by printing. On the contrary, the printing control can only be obtained when the substrate color, the ink color of the three primary colors, the ink overprint, and other printing variables are relatively stable and balanced. In fact, the balance of these important parameters will continue to change with changes in printing, such as to match the changing basic materials, inks, and substrates. Pre-press artists have used all the control, color management and measurement systems, but still can not guarantee that they can obtain consistent, balanced halftone products. The reason is that small changes in substrate color, ink opacity, or overprinting have not been discovered by the printer.
Gray balance and three primary colors ink overprint
In printing, the three primary colors of ink are mixed in different proportions to obtain the desired color spectrum tone value. The density and correctness of the three primary colors of ink printed on the substrate have a direct relationship with the printing staff. As a guide for obtaining the correct ink contrast, density balance should be operated in accordance with FIRST (Flexographic Image Reproduction Specifications and Tolerances).
Printing operators can only measure and set ink density within a limited range, which is described in various publication guides such as FIRST and SWOP. But these density ranges can obtain a large range of overprint ink colors, and regardless of whether the ink is pure and transparent, or whether the substrate is pure white. In general, the application of the pre-press color management system that currently exists actually is not ideal for controlling printing colors.
The ink density range according to the instructions can be used for any ink overprinting sequence, namely YMC, YCM, CMY, CYM, MCY or MYC. But does each sequence produce the same color? No.
Even when the solid density is controlled to an absolute value, each overprint sequence will produce different overprint colors of red, green, and blue, because each printing ink formulation has its own different properties, such as ink opacity that affects the coverage rate. Therefore, the surface energy of the ink dried film layer printed first will affect the adhesion characteristics of the wet ink printed later.
Yellow pigments have poor coverage, and magenta and cyan pigments have good coverage. But the surface energy of yellow pigment ink is high.
The first step in color management in printing is to determine the best ink overprint sequence and density balance that can provide a high color rendering range. The GATF Association developed a simple color hexagon color map many years ago to visualize the ratio of different colors. The density meter can display the quality of the color by measuring the hue deviation, gray scale and overprint color and compare it with the three primary colors.
For example, the three corners of the hexagonal color diagram that are not adjacent to each other are the ideal primary ink color (YMC), the other three corners are the overprint composite color (RGB), and the center of the hexagon is the neutral color (white to gray) To black). The greater the color strength of the ink, the closer to the corners, the farther away from the neutral color.
When the actual printing colors and composite colors are distributed in the hexagonal color map, the density, hue difference, and gray value of the three primary colors (CMY) and composite colors (RGB) are displayed. Because the ink is not too ideal, the distributed hexagons (irregular) will not be the same size as the entire ideal hexagon color map, but it can be used for optimal printing. Therefore, using the GAFT method for irregular hexagonal distribution to display the printed three primary colors and composite color information, you can get the best density and overprint sequence.
Zhejiang Lamon Technology Inc. , https://www.chairesbaby.com