Several Factors Affecting The Quality Of Color Printing

1. Change of outlets

       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.Several Factors Affecting The Quality Of Color Printing

        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 Iarea 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, Several Factors Affecting The Quality Of Color Printing

       It is necessary to change the dot area coverage greatly; On the contrary, in order to distinguish the two darker tones, the dot area coverage can be achieved with only a small change.Several Factors Affecting The Quality Of Color Printing

       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

2. 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. Several Factors Affecting The Quality Of Color Printing

       The ink layer is too thin, and the ink cannot completely cover the printing area of the substrate. Several Factors Affecting The Quality Of Color Printing

        The color must be light and the gloss is not enough. 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. Several Factors Affecting The Quality Of Color Printing

       Therefore, controlling the thickness of ink film is an important means of color restoration. The ink film thickness is not only restricted by the properties of ink and paper, but also affected by printing conditions and environmental factors.Several Factors Affecting The Quality Of Color Printing 

       To sum up, it mainly includes the following points:Several Factors Affecting The Quality Of Color Printing        

           printing pressure, printing speed, ink supply, paper performance, blanket quality, temperature and humidity, etc. 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. When printing, it is necessary to try to select ink with large color gamut. Several Factors Affecting The Quality Of Color Printing

       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

3. 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. Paper smoothness is proportional to ink transfer rate in a certain range.Several Factors Affecting The Quality Of Color Printing

          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.Several Factors Affecting The Quality Of Color Printing

        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.Several Factors Affecting The Quality Of Color 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

4. Printing process

         Offset printing uses the principle of immiscibility of oil and water to indirectly transfer the ink on the printing plate to the paper through blanket under a certain printing pressure. Several Factors Affecting The Quality Of Color Printing

       In printing, the normal transfer of ink is the condition that determines the color of printed matter. In practice, there are many factors affecting the quality of ink transfer, mainly including printing speed, printing pressure, printing color sequence, ink balance and so on.Several Factors Affecting The Quality Of Color Printing

1) Printing speed

       The printing speed determines the contact time of the ink from the printing plate to the paper. Printing speed and printing pressure are two interactive factors. Under the premise of a certain pressure, the faster the speed, the less the contact time, so the shallower the density.Several Factors Affecting The Quality Of Color Printing

        Usually, the higher the printing speed, the greater the corresponding printing pressure, so as to have good ink transfer quality. In order to ensure the consistency of printing color, the printing speed must be consistent.Several Factors Affecting The Quality Of Color Printing

2) Printing pressure

         The function of printing pressure is to eliminate the gap between each contact surface in order to complete the smooth transfer of ink. The ratio of the amount of ink transferred to the surface of the substrate to the amount of ink applied to the printing plate is called the ink transfer rate. The printing process always hopes to obtain high ink transfer rate under certain conditions. Several Factors Affecting The Quality Of Color Printing

        The ink transfer rate is related to many factors, such as printing pressure, printing speed, printing suitability of printing ink and so on. When the printing speed and printing conditions are certain, and the printing suitability such as paper smoothness and ink plastic viscosity are certain, the relationship between ink transfer rate and printing pressure is roughly as follows: Several Factors Affecting The Quality Of Color Printing

        when the printing pressure is too low, the ink can not fully contact the paper surface, resulting in the emptiness and incompleteness of the imprint; When the printing pressure is appropriately increased, the ink transfer rate also increases, which is almost linear with the growth of printing pressure.Several Factors Affecting The Quality Of Color Printing

          However, when it increases to a certain value, the ink transfer rate no longer increases with the increase of printing pressure. On the contrary, when the pressure is too high, the phenomenon of severe punishment and expansion of mesh points will occur, resulting in blurred imprinting and reduced density.Several Factors Affecting The Quality Of Color Printing

           Also, the pressure is too high. A series of problems such as slip and friction will also occur, resulting in inaccurate overprint, which seriously affects the correct reproduction of color.Several Factors Affecting The Quality Of Color Printing 

       Therefore, in the printing process, not only the printing pressure is appropriate, but also the printing pressure must be consistent in the whole process of printing the same batch of products, so as to avoid inconsistent color.Several Factors Affecting The Quality Of Color Printing

3) Printing color sequence

         In theory, which color should be printed first and which color should be printed later should be able to obtain the same color rendering effect, but it is not.Several Factors Affecting The Quality Of Color Printing

       First of all, the first printing ink is mostly in direct contact with the paper, and then most of the printing ink is printed on the ink layer. In this way, due to different printing materials, the ink transfer rate is also different under the same conditions. Several Factors Affecting The Quality Of Color Printing

          Secondly, due to the differences in ink transparency, viscosity and ink absorption of paper, the surface reflectivity of each color ink after printing is also different: due to the factor of ink coverage,Several Factors Affecting The Quality Of Color Printing

        The back color must cover part of the front color imprint, so that the color of printed matter always focuses on the back color or the mixed color of the back color.Several Factors Affecting The Quality Of Color Printing

        Especially the part where the multi-color dot levels are not overlapped. Due to the inconsistent color sequence of picture color, it is most likely to cause the disadvantage of color deviation between printed matter and proofing.Several Factors Affecting The Quality Of Color Printing

         In order to eliminate color deviation between multi-color press printing and proofing, it is important to unify the color sequence between them.Several Factors Affecting The Quality Of Color Printing

        Therefore, the color sequence is a complex process problem, which must be comprehensively selected according to the nature of the original picture, the characteristics of ink and paper, and the structural characteristics of the printing press.Several Factors Affecting The Quality Of Color Printing

4) Ink balance

         In offset printing, it is very important to control the ink balance. Improper control of ink balance will also severely affect the quality of color reproduction. Several Factors Affecting The Quality Of Color Printing

       There must be no water in lithography, but too much or too little water on the printing plate will directly affect the printing quality and the smooth progress of production.Several Factors Affecting The Quality Of Color Printing

        When the water content is too large, the printed matter will turn white, and water stains will be generated in the field, which will make the imprint weak and the ink color is different. Several Factors Affecting The Quality Of Color Printing

        At the same time, the deformation of the paper increases, and the graphic overprint is not accurate; Several Factors Affecting The Quality Of Color Printing

       When the water content is too small, first there is ink pollution in the blank part of the print, causing the version to be dirty. Several Factors Affecting The Quality Of Color Printing

       With the extension of time, the ink gradually blocks the non inked part, resulting in “paste version”.Several Factors Affecting The Quality Of Color Printing

       In addition to the above main factors. Only the increase of printing machine working time leads to the increase of ink temperature, which can not be avoided. Several Factors Affecting The Quality Of Color Printing

       The increase of ink temperature will lead to the decrease of ink viscosity, and the change of ink viscosity has a very important impact on the splitting and transfer of ink, which will inevitably lead to the change of print color.Several Factors Affecting The Quality Of Color Printing

5. Conclusion

       Obviously, the above factors do not work in isolation. But interrelated, interactive and interactive. The smoothness of paper directly affects the transfer rate of ink, the adjustment of printing pressure and printing speed. Several Factors Affecting The Quality Of Color Printing

        The color of the paper itself directly affects the color rendering effect of the ink and the quality of color reproduction.Several Factors Affecting The Quality Of Color Printing

       The performance of paper and ink and various factors in the printing process have almost caused a certain degree of dot change.Several Factors Affecting The Quality Of Color Printing

       Human visual characteristics also put forward certain requirements for the control of dot size.Several Factors Affecting The Quality Of Color Printing

        The characteristics of the ink itself also directly affect various factors in the printing process. Several Factors Affecting The Quality Of Color Printing

       The changes of some parameters and in the printing process will also cause the changes of the performance of the ink itself. Several Factors Affecting The Quality Of Color Printing

      These parameters, combined with the processes of prepress plate making and Postpress processing, jointly affect the color reproduction quality of color reproduction. Several Factors Affecting The Quality Of Color Printing

      To accurately control and copy color, color separation, Internet access and printing should cooperate with each other, and the influence of various factors and their relationship should be comprehensively considered to achieve the best color reproduction effect.Several Factors Affecting The Quality Of Color Printing