Several Factors Affecting the Quality of Color Printing

      Color printing is to reproduce the color and tone of the original by overprinting three printing plates of yellow, yellow and green with different dot angles, and add a black plate to make up for the lack of dark tone. In offset printing, due to various reasons, dot expansion is inevitable.Several Factors Affecting the Quality of Color Printing

      The change of dot size will cause the change of color depth of printed matter. At the same time, it is worth noting that the color depth of printed matter is not always linear with dot percentage. In optical density value.Several Factors Affecting the Quality of Color Printing

      At the small end, the influence of the increase of dot area on the tone density is much smaller than that at the large end of optical density. In other words, in order to make the difference between two brighter tones, it is necessary to change the dot area coverage greatly; Several Factors Affecting the Quality of Color Printing

      On the contrary, in order to distinguish the two darker tones, the dot area coverage can be achieved with only a small change. It also shows that in the bright tone area, the small change of dot percentage has little influence on the tone, which is difficult to be detected by the eyes; In the dark tone area, the slight change of dot percentage will cause the significant change of tone. Several Factors Affecting the Quality of Color Printing

      Therefore, the influence of the change of dot size on the color of image reproduction is complex. In practice, the control of the dot size of the dark part is particularly important.Several Factors Affecting the Quality of Color Printing

 Ink

      The structure and properties of ink have a direct impact on the reproduction of color.Several Factors Affecting the Quality of Color Printing

      In color printing, the quality of printed products is often measured by parameters such as ink field density, dot increase, printing contrast and overprint rate, which are closely related to the ink film thickness on the printing sheet. The ink layer is too thin, and the ink cannot completely cover the printing area of the substrate. The color must be light and the gloss is not enough. Several Factors Affecting the Quality of Color Printing

       Generally, the ink film thickness is 1.0 μ M, the density will not increase if the ink film thickness is increased. On the contrary, because the ink layer is too thick, the dot will increase, and the levels, tones and colors will change significantly, resulting in color deviation. Therefore, controlling the thickness of ink film is an important means of color restoration. Several Factors Affecting the Quality of Color Printing

       The ink film thickness is not only restricted by the properties of ink and paper, but also affected by printing conditions and environmental factors. To sum up, it mainly includes the following points: printing pressure, printing speed, ink supply, paper performance, blanket quality, temperature and humidity, etc. Several Factors Affecting the Quality of Color Printing

       Different inks have different film thickness in order to achieve a certain required density value due to their different properties, such as different coloring power.Several Factors Affecting the Quality of Color Printing

          Therefore, controlling the ink film thickness is the key, and the defects of the ink itself should be understood. As we all know, the ideal three primary color ink mixed in equal proportion can produce neutral gray, while the actually used three primary color ink mixed in equal proportion can never produce neutral, only dark color. Several Factors Affecting the Quality of Color Printing

      The correct reproduction balance is the basis of color printing. The unsatisfactory ink itself obviously brings some difficulties to the correct reproduction of color.Several Factors Affecting the Quality of Color Printing

           At the same time, The color range that can be reproduced by ink overprint (color gamut) is the smallest of all color gamuts. Ink produced by different manufacturers and different types of ink produced by the same manufacturer can reproduce different color ranges.Several Factors Affecting the Quality of Color Printing

       When printing, it is necessary to try to select ink with large color gamut. The larger the color gamut, the smaller the loss of color information, and the higher the fidelity of color reproduction; on the contrary, the smaller the color gamut, the more color information The greater the interest loss, the correct reproduction of color will be affected.Several Factors Affecting the Quality of Color Printing

 Paper

             Different printing materials have different printability. The smoothness, ink absorption, surface strength, whiteness, sizing and scalability of paper are closely related to the quality of printed matter. Several Factors Affecting the Quality of Color Printing

        This paper mainly discusses the influence of smoothness and whiteness of paper on color restoration. The smoothness of the paper determines the close contact between the paper and the printing plate. Several Factors Affecting the Quality of Color Printing

       Paper smoothness is proportional to ink transfer rate in a certain range. When the smoothness is high, even if the ink layer of the printing plate is very thin, the connecting material of the ink will quickly form a fixed ink layer on the paper, which is conducive to the overprint of the next printing color, but the transfer rate will not increase when the ink layer increases to a certain thickness.Several Factors Affecting the Quality of Color Printing

        Coated paper is smoother than offset paper, and even color prints can be obtained with a slight change in ink layer thickness; On the contrary, offset paper is poor and the transfer rate is low, which is not conducive to the restoration of color.Several Factors Affecting the Quality of Color Printing

        The whiteness of the paper, that is, the whiteness of the paper, that is, the ability of the paper to reflect the visible light of each wavelength in equal proportion. Except for a few colored papers, most of the printing papers are white paper. Different papers are different. For printing, of course, the higher the whiteness of the paper, the better.Several Factors Affecting the Quality of Color Printing

         Only nearly pure white paper that can reflect all visible light can give full play to the color characteristics of ink. If the color of the paper is yellow, blue or red, it will make the printing produce color deviation, which will affect the hue, lightness and saturation of the printing. The brightness of the paper will also affect the contrast of the picture level.Several Factors Affecting the Quality of Color Printing

        If the whiteness of the paper is good, the sense of hierarchy and clarity of the picture will be improved accordingly. On the contrary, it will make the printing color gray and poor contrast.Several Factors Affecting the Quality of Color Printing