At present, there are generally two problems in the printing process of newspapers: First, although the layout is clean and the lines are less dirty, the level of image tone loss is larger, the level is shallower, and the tone is shortened; secondly, the entire image is The adjusted outlets are basically faithfully restored, 2% outlets are intact, and 97% outlets are not affixed. However, the film edges and paste stains left during the exposure process are numerous, resulting in a significant increase in the speed of platemaking in addition to the increase in winning workload. . The former requires the exposure time to be as long as possible to remove a large number of trace marks and kimono points, but it affects the reproduction of image tone levels; the latter requires the exposure time to be as short as possible to meet the requirements of image level faithful transmission, but the layout is easy. dirty. Therefore, the printing of newspapers is always in such a contradiction in the choice of exposure time. At present, there are two kinds of traditional platemaking techniques and desktop platemaking techniques in the art of newspaper making, as shown in Fig. 1 and Fig. 2 . Under the traditional platemaking process conditions, since the plate is artificially imprinted, it is often necessary to use a longer exposure time (sometimes supplemented by a “double exposure†of the scattering film) to remove lines and dirt to ensure that the plate is clean and tidy. Under the desktop platemaking process conditions, the image layer transfer requirements can be satisfied in the exposure time, and the goal of image faithful reduction can basically be achieved, but there are still line marks around the printing plate, and the dirty work load is still not small. The "mask" exposure method can solve the above problems. The “mask†mentioned here is different from the mask in the photographic color separation plate. It utilizes the diffusion effect of the scattering film on the light to remove the line marks. At this point, it is the same as the scattering film commonly used in the current printing machine. The “exposure†method is similar, but there are differences in the specific operations. The method of making “masks†is relatively simple. The first step is to take a piece of polyester film that is slightly larger than the size of the folio paper and lay it on the imposition paper. Impose table paper requirements, set the necessary printing rules, and then align the film base on the aligned printing plate and align the rules. In the second step, take a scattering film and cut it into strips to cover the printing plates. Adhere to the surrounding frame and stick it with clear tape.When in use, after the printing plate is aligned with the rules, place the mask on top of the plate and align it with the rules. Then use the “mask†exposure method when printing. Although a mask is added, it is easier to operate than the conventional printing method, and therefore it is very practical. In order to have more understanding of the “mask†exposure method, we have exposed this method with a scattering film. The method makes a comparison, in the diffusion film exposure method The scattering film covers the entire layout, which also affects the quality of the image dots while eliminating line marks and dirt.The diffusion of light causes the back of the dot to receive light, forming virtual halo dots, and even causing the loss of small dots in the image. When the conditions of development change (such as changing the development time within the range of normal development latitude), the dot size will be significantly affected, so that the printing plate dots will have poor reducibility and the resistance to printing will be reduced.In the "mask" exposure method, the scattering film covers only The edges of the original film have no effect on images and other images, and in a suitable exposure time, the image dots can be faithfully reproduced, and at the same time, film edges and line marks can be eliminated, thereby successfully solving the problem of the newspapers. A major contradiction in the edition has greatly improved the printing quality of newspapers (especially color newspapers).From the above analysis, we can see that the “mask†exposure method came into being with the development of the desktop plate making process. A certain use value. "This article is a summary of the author's work experience, and it is not appropriate. Please contact me for correction.