High-fidelity printing technology should know

Q: What are the main differences between high-fidelity color printing technology and four-color printing? What is the difference between the method of adding four colors and spot colors?

A: High-fidelity printing is usually based on the conventional four-color printing of basic color inks C, M, Y, and K. New primary color inks are added, and new color separation algorithms are used to expand the printing color gamut. Colors in the original image that are outside the four-color printing gamut give better print reproduction. At the same time, because the high-fidelity color separation algorithm is different from the conventional four-color color separation algorithm, the brightness characteristic of the printed color can be made closer to the brightness characteristic of the perceived color, and therefore, the light effect of the printed image is more realistic.

The so-called four-color plus spot color method is still based on four-color color separation, four-color color other than the general can only be used in the field, flat net, gradient and other methods. Unless manually changing the hierarchical color curve of the image separation output, while also borrowing one of the four color separation channels for the spot color, the dynamic range of the saturation and brightness is modified. Otherwise, the spot color cannot be used for the print copy of the image and cannot be improved. Image printing effect.

Q: How does high-fidelity printing increase the color gamut? What is the difference between using "Little Red", "Little Green", "Little Blue" and other methods?

A: The conventional four-color printing gamut has the following features. The color components of the three primary color ink combinations of C, M, and Y are distributed in the three hue intervals of the printing color gamut. For example, the M+Y range includes magenta, rose red, red, orange, yellow, and other hue colors. The Y+C range includes yellow, green, green, green, and blue and other hue colors. The C+M range includes hue, cyan, blue, violet, magenta, and other hue colors. When the third color is added to the corresponding hue interval, the opposite color is used. It forms a neutral gray with a portion of the other base color, which not only reduces the brightness of the color but also reduces the saturation of the color. The color within the printing color gamut can increase the amount of ink constituting the color component, reduce the amount of ink constituting the neutral ash component, and increase the saturation of the color while maintaining the hue and brightness unchanged. In the color of the color gamut boundary, a certain amount of ink has reached the maximum, that is, the dot area has reached 100%, there is no way to add color components. Therefore, people thought that adding a new ink in the corresponding hue interval can increase the color saturation without reducing the brightness and changing the hue. For example, increase red to the M+Y hue interval, increase green to the Y+C hue interval, and increase blue to the C+M hue interval. This is the method used by previously experienced printers to expand the print color gamut. This idea makes sense, but it is very difficult to achieve the desired results on the basis of four-color separation.

In order to maintain the similarity of printed color tone characteristics to the original, the condition for using the new color is that the tone characteristics of the original primary color combination should be adjusted appropriately to accommodate the addition of the new ink. As described above, in the four-color separation color gamut, each primary color affects two hue intervals. For example, when the amount of magenta is changed, it affects not only the color of the M+Y interval but also the color of the M+C interval, and may also produce a corresponding medium color. Sexual deviation. In order to accommodate the addition of red ink, adjust the linearity of magenta and yellow ink tone, and close to the ideal effect in the M+Y interval, the opposite effect may be produced in the M+C interval and Y+C interval, including hue deviation, neutral gray Deviation, color saturation, and color tone distortion. Each change in the amount of base color, each new ink is added, may have an ideal change in the part of the hue interval, while producing adverse changes in the other hue interval. Using this method requires a certain theoretical foundation of colorimetry and rich practical experience. After repeated adjustment experiments, it can finally achieve relatively satisfactory results. This method is usually used for printing and copying, and most of them are based on color components. Printed images generally have a high degree of color saturation, however, color tone distortion is more obvious, more loss of detail, if you can see the neutral gray part, there is generally more obvious color deviation. The overall impression of printed images is that the colors are heavy and the lighting effects are not clear enough.

High-fidelity separation is different from conventional four-color separation. Although the principle of expanding the printing color gamut by adding primary color inks is the same, this is the only way to expand the color gamut of printing at this stage.

However, the basic color ink combination method is different, that is, the color composition of the hue interval is different. The amount of the base color ink is determined based on the optimal color index as the standard, and the mutual influence between the basic color ink usage is effectively controlled. For example, in the original regular four-color M+Y hue interval, increase the orange primary color to form two separate hue intervals of M+O and O+Y, and the coordinates of the corresponding secondary superimposition color saturation and brightness parameters exceed the conventional The color gamut boundary of the four-color separation of the M+Y hue interval. Adding green and blue base color inks to the corresponding hue interval and forming a new hue interval all have similar effects.
The high fidelity color separation algorithm, applying the principle of colorimetry, aims at visually perceiving the characteristics of color, and the ink combination color is preferred among all available ink color combinations. With the latest international gamut space mapping strategy as a guide, relative to the input color chromaticity parameters, the saturation and brightness of the ink color are respectively adjusted on the basis of equal hues, so that the perception effect of the printed image is relatively the most similar to that of the original image. Perceived effect. Basic color inks can be flexibly selected as needed. High-fidelity color separation systems are delivered to customers with software products, which are as simple and fast as four-color systems.

Q: What are the conditions for enterprise application of high-fidelity printing technology?

A: The high-fidelity color separation system is a stand-alone software system running under the Mac computer 9.x or 10.x operating system. After hours of training, the operator can apply it independently. The color separation system works best when reading RGB mode data. There are no special requirements for typesetting software and platemaking equipment. Need to buy basic inks for high-fidelity printing. As with conventional four-color printing, the performance of printing equipment affects production efficiency and product quality. High-fidelity color printing, using a monochrome machine to a seven-color machine can be more efficient. Offset printing, gravure printing, flexo printing, screen printing, etc. can apply high-fidelity printing technology.

If the technical personnel of the enterprise understand and grasp the printing and copying project more, the understanding of the nature of the high-fidelity printing process will be more in-depth, and it will be easier to give full play to the quality advantages of high-fidelity printing and ensure the stability of the printing process.

If corporate sales personnel have a deeper and more comprehensive understanding of market demand, the observation and characteristics of high-fidelity printing products will be more careful and easier to communicate with customers and achieve win-win results.

Q: Which products are suitable for high-fidelity printing? How to use this technology?

A: High-fidelity printing technology is suitable for printing products with color images. The bright, bright colors in the image manuscript can be reproduced more realistically. The effect of light changes in the image can be reproduced more realistically. This is the reason for the naming of high-fidelity prints.

Compared with four-color printing effects, high-fidelity printing products have obvious quality advantages. It can attract more attention and arouse greater interest. It can mean that its owner is different, more powerful, more tasteful, and more pursuing, as well as other brand-name products. This shows that high-fidelity printing technology can meet or can pull the needs of high-end customers, is the printing company must have the ability to produce brand-name products.

High-fidelity printing technology is divided into two parts, a high-fidelity color separation system and a high-fidelity printing process. High-fidelity color separation system provides a variety of color separation models, operators can use directly. Open the image electronic file in the system, specify the color separation model, enter the color separation module to generate color separation files, the entire process does not exceed one minute. You can also use "hot folders" for batch operations to increase work efficiency. Separation files are used for typesetting and are the same as four-color separations. Select all the primary color ink channels when output, and set the corresponding screening parameters. As you can see, the high-fidelity color separation system is simple and quick to use.

Reprinted from: Printing Industry