A. Plate-making operation is not standardized caused by yellow, magenta, green a color printing plate network too deep or too shallow. During the printing process, the intensity of the copy light source, the spectral characteristics of the photographic film does not match, or the exposure time is improper; the pH value of the developer and the length of the development time are inappropriate, etc., which may cause the printing plate network to be too deep or too shallow The This printing plate on the machine printing, the color of the screen is inevitable.
Therefore, the plate in the machine must first identify its quality, the identification of the plate network can be used to contrast the magnifying glass, yellow, magenta, green, black original film, carefully look at the corresponding plate pattern the same part of the bright Tune, in tune, dark tone regional network situation, that is, light tone parts 2% of the small outlets, the plate should be able to be the same drying, printed on the 3% of the outlets should be able to print out. If the printing plate on the 2% of the small outlets do not come out, then the printing plate is too shallow, not applicable. With the identification of the plate with the film on the film 2% of the small points of the method to identify the same version of the original film on the same site with 97% of the dot. If the printing plate on the site and paste, then that the plate sun deep; if this part of the gap between the area of the area expanded, then the printing plate is too shallow, it should be re-sun.
B. Ink color improperly arranged or three primary colors ink does not match. Screen printing process, caused by the ink color shift fault, mostly because the existing local production of three primary colors of ink are different degrees of color shift, which the whole screen will produce varying degrees of color cast, especially in the middle The impact of more serious impact. But a small amount of color can be corrected from the ink compatibility.
C. Print arrangement is unreasonable. Compared with the proofs, sometimes the printed ink, paper and field density are the same, but the printed matter is still yellowish, reddish or bluish or overprint color ink blending phenomenon occurs. What is the reason for this? First, the proofing machine is generally monochrome wet pressure dry printing, ink adsorption, transfer rate is more appropriate; Second, the machine structure, pressure, speed with the actual printing is not the same; Third, high-speed multi-color printing when the color arrangement is unreasonable. I believe that the order of the arrangement of irrational order will not only cause color shift fault, but also make the print pattern color due to wet pressure wet overprint caused by mixed color consequences.