The color characteristics of high-fidelity printing are manifested in two aspects. First, the printed color space is expanded, brighter and more vivid colors are added, so that the prints look closer to the colors of real scenes, as shown in Figure 3. Secondly, the linearity of the printing color is different from that of conventional four-color printing. The visual perception is closer to the effect of the spectral color change, and the print layering is more real and the three-dimensional feeling is stronger.
Figure 3 High-fidelity seven-color printing color gamut
The main reason for the increase in high-fidelity printing color space is the addition of new and appropriate primary color inks based on CMYK, and all primary color inks other than black inks are all involved in matching the color components in the input color. The new basic color inks include O, G, B, etc. These inks and adjacent C, M, Y overprint secondary colors, color brightness and color saturation exceed the C, M, Y overprint secondary colors, but also can be used Adjacent trichromatic inks are overprinted to further increase color saturation. Therefore, the printed color space is predictably and modifiable.
While expanding the color gamut of high-fidelity printing, it also pays great attention to the maintenance of the linearity of the hue of printed color hue. In the conventional four-color printing, the saturation of the color is often emphasized, and less emphasis is placed on the authenticity of the gradation linearity. The color components of the different tone colors in the high-fidelity printing color space match the input RGB color hue and saturation tone characteristics. Ink color as faithfully as possible to maintain this feature, so that the color visual effects of printed color images and actual scene color perception closer.
The high-fidelity color separation is performed in the CIERGB color space, and the input RGB color will obtain luminance and chromaticity characteristics closer to the spectrum color. The different basic color inks respectively match the chromaticity parameters of the input colors in different hue intervals, for example, red matches M, O and a small amount of Y, and green matches Y, G and a small amount of C. The basic color ink channel setting ensures that the printing color gamut will be expanded and the tone will be linearly restored. Compared with four-color printing, the color brightness is not reduced to a certain extent due to the increase in saturation. This is a very valuable feature that cannot be achieved with conventional four-color printing.
Do not think that high-fidelity color printing technology is only suitable for commercial prints, but in fact it is equally or more suitable for the field of Packaging and printing. As we all know, the traditional metal printing methods include lithographic offset printing and roll printing, and in the case of Tinplate, offset printing is mainly based on flat offset printing. Because the tinplate substrate is not absorbent, the oven curing process is used to volatilize the solvent in the ink. However, due to limitations of the printing equipment and process environment, many factors such as the substrate and the ink are also affected. For a long time, tinplate printing products have low color saturation, a small color gamut, poor pattern reproducibility, easily deformed dots, and precision and chromatic aberration control ratios. Other printing is more difficult. Therefore, in order to truly reproduce the original image style, a high-fidelity, wide-gamut high-fidelity metal printing technology came into being.
The advantage of high-fidelity color printing is that if it is seven-color printing, the color gamut will be expanded by more than 30% compared with conventional four-color printing, which greatly improves the ability to express vivid colors; its printing color tone is more linear and accurate, and it enhances the performance of color shade changes. The ability to adjust the linearity of its brightness, not only makes the color change in the darker tone more pronounced, but also makes the printed image more three-dimensional. The ability of high-fidelity printing technology to express, is exactly what high-grade color printing needs. Compared to high-fidelity printing quality, conventional four-color printing will retreat to a second-rate quality level. In the future high-end printing customer market, companies that cannot provide high-fidelity printing quality will lose their qualifications to undertake orders.
(to be continued)
