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Improve printing efficiency

if prepress producers know more about printing expertise, it will be of great benefit to improve work efficiency. Printing professional knowledge related to plate making correct selection of image scanning resolution is inseparable from image scanning when plate making. It is very important to correctly set the image scanning resolution. If the image resolution is set too low and the sawtooth of the scanned image is too high, the computer processing time will be wasted and it is not beneficial to improve the image accuracy. Generally, the image scanning resolution two plus line number is only the magnification fire coefficient one, and the plus line number is related to the paper used, so you must know the paper used in the printing product and the original magnification before making. When the original is not scaled, if it is printed on paper, the number of lines added is one, then the image scanning resolution is one. If it is printed on high-quality coated paper, the number of lines added is one. At this time, the image scanning resolution should be taken as more appropriate. When processing line drafts, the scanning accuracy should choose the color separation mode. When selecting the scanning color separation mode, you can also choose the mode. Usually, the printing color separation mode is selected, because the printed matter reflects various colors by mixing four colors in different proportions. No matter what mode the picture is, it must be converted to mode when it is output after *. Tone reproduction printed matter is expressed by the area ratio of points. The tensile modulus of a glass fiber can reach up to 90GPa, and the * high density of the transmitted original can reach about of the reflective original, while the * high density of the printed matter is one, so it is impossible to faithfully record all the information of the original on the printed matter. And different printing paper can reproduce different tone values. In order to achieve the desired printing effect after scanning different originals, the gradient of the originals must be compressed. Before scanning, first analyze the original to determine whether it is a normal original, underexposed or overexposed, adjust it according to different hierarchical curves, and correctly select high light and dark field calibration. Color restoration completes the reproduction of the original tone on the printed matter based on the correct reproduction of the tone. In the seven color separation software, when the dot enlargement value of the ink paper printer used, the total amount of ink and the gradient length of the black version of the four-color overprint are given, the computer will automatically calculate and generate a set of gray balance curves based on these data, so as to complete the color restoration. The color deviation of the original can be adjusted with the help of the measurement tool in. Sharpness sharpens the printed image by emphasizing the subtle changes of the image. Different methods should be adopted according to different original papers. For example, picture 1 on paper can be more emphasized when sharpening because it is printed by high-speed rotary machine. When dealing with character originals, pay attention not to emphasize too much, otherwise the obvious outline will appear untrue. Original blur through the sharpening function, you can get a clear image in the paper kernel. Image sharpening in image processing software is achieved through the rational application of radius quantity flail threshold data. At the same time, because of reducing the amount of three primary color ink, the cost is reduced. When making, we should reasonably choose the tone of the black version according to the characteristics of the original. For example, the short key or middle note black version should be used for the original landscape photos, figure watercolors, etc. which are mainly color, and the long key black version should be used for the reproduction of the original such as traditional Chinese painting, which is mainly achromatic. The function of trapping is to try to compensate for this small gap between different color patches due to inaccurate overprinting. Trapping can be carried out inside the typesetting software, or the format file can be output to a special workstation. The finer the print, the higher the overprint accuracy, and the lower the trapping value. For example, when printing with coated paper on a sheet fed offset press, the trapping value is about two. When printing with paper on a high-speed rotary press, the trapping value is set as Liu auxiliary line or the standard line of post press folding. The signal strip is a means for implementing the digital measurement and control of printing quality, used to observe and evaluate the printing quality of color prints, and provides an objective standard for the control and management of printing quality. It is mainly used to evaluate the color reproduction and tone reproduction of printed matter, and it can also be used to detect the overprint accuracy, the exposure of double printing plate, the development condition, the resolution of printing plate, etc. it is a necessary auxiliary tool. These should be added at the time of output. The film output from the film haze field density linearization test requires that the film base be clear, transparent, clean and free of dirty spots, the text strokes are continuous, the field density is above, the dots are flat, and the shape is regular. The output time point is reproduced truly, without expansion or reduction. In actual production, due to the change of development processing conditions and the change of exposure of Phototypesetter, the correct point restoration cannot be guaranteed. Therefore, in order to ensure the stability of the quality of Phototypesetter film, the film must be linearized every day before work to detect the laser exposure and the processing conditions of the developer, so as to ensure that the points on the document are correctly transferred to the film. Phototypesetting output precision output precision is measured by * high exposure points per inch, that is, phototypesetting output resolution, expressed in. Generally, the accuracy of Phototypesetter is up to or higher. During Phototypesetting, the appropriate output accuracy should be selected according to the number of lines added to the image. Select phototypesetting output resolution as when the number of lines added to the printing is selected, then select phototypesetting output resolution as angle. When two or more plates are superimposed, theoretically, Pu insulation materials with flame retardancy reaching B1 and B2 levels will not produce moire when the line angles are completely coincident, but it is impossible to completely coincide in actual printing, and moire will appear at this time. Therefore, in order to avoid rabbits, you can also purchase multiple sets of equipment for production at the same time, and set a certain angle for various color plates when adding time, that is, adding angle. The line adding offset printing mainly passes through the multiple transmission of points, and then it is integrated and imaged. The color continuous tone manuscript is converted into point image information by scanning and color separation. During printing, the points with different sizes recorded on the four-color printing rice are used to represent the shades of the picture. The size of the points depends on the number of lines added and the percentage of points. The number of lines added per inch is determined by the printing method and the paper used. Generally, the paper adopts a ring of offset paper, coated paper or even professional knowledge related to output. The output film must have a cutting line regular line signal strip, etc. The cutting line has an outer tangent and an inner tangent. The distance between the two lines is usually the regular line of the incision and the middle line of the corner line. It is not only a tool to check whether the four-color film is correct, but also a necessary professional knowledge related to the printing machine. The printing methods include self turning printing, overprint printing, and heaven and earth turning printing. Take the four format printing machine as an example. There is an open page, double-sided and four-color printing, which often adopts the self turning printing method. During plate making, the four pages are assembled head to head or foot to foot into a set of quarto plates in a certain order, and then printed on the machine after printing. When one side is printed, the printing plate does not move, the bite of the paper does not change, and the paper is turned over and printed on the other side, that is, a self turning printing is completed. The double side of the paper is used as the nip for Tiandi printing. Due to the size error of the paper when cutting, the two side nip is easy to cause inaccurate overprint, so it is not used in general, unless it is unavoidable. The biting distance must be fully considered when making, so that the printing can be carried out smoothly. For example, the above-mentioned turning over printing method adopts biting on both sides, because the paper specification is certain, so the size of the finished product must be reduced accordingly. Otherwise, some patterns will not be printed, resulting in defective products. Color text the words with various colors superimposed should try to use bold fonts with thick strokes. For small characters and thin lines, try not to register, otherwise the text will be blurred due to the overprint error generated in the multi-color printing process, which will affect the beauty. Similarly, when using white words on the full page background, do not use too fine fonts. Due to the purity of the ink and the printing machine, if black is used as the background color of the full version, the printed black is not full enough. Therefore, when making the full version of the field black, it is recommended to use black cyan or black product as the background color. In this way, the black effect is better. Dot enlargement due to the influence of roller pressure, ink absorption of paper and some optical factors, dot enlargement is bound to occur in the printing process. In sheet fed offset printing, the expansion value is, while in web offset printing machine, the point expansion value is about that when scanning, the scanner software will compensate for the point expansion, so the factor of point expansion of the printing machine must be considered when making. Professional knowledge related to binding. Before making the cut, you must know the finished product size of the product, and then add the cut on the basis of the finished product size, that is, the designed layout size. It should also be noted that sometimes the folding methods of manual folding and machine folding are different, which determine the different order of making up. Therefore, only by thoroughly understanding the requirements of each process can the prepress production personnel ensure the correct order of making up. At the same time, when making a magazine or book, we should pay attention to the unity of the cover and the text. If the cover adopts the head to head combination of expanded perlite insulation products gb/t10303 (2) 001, the text should also adopt the head to head combination. If the cover adopts the foot to foot combination, the text should also be foot to foot combination, which must be consistent. When making a book edition, you should understand the terms such as the front cover, back cover, spine and mouth. For a book with a spine, you should be able to calculate the thickness of the spine according to the number of pages of the book and the paper used, so as to correctly place the text position of the spine and center it left and right. To sum up, only when prepress producers know more about and master printing knowledge, can they produce a printing plate that meets the requirements of printing and binding, and fully reflect the intention of the designer. Only in this way can we better provide high-quality services for the latter, ensure the smooth progress of production, ensure the quality, and enhance the competitiveness of enterprises

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