Quality inspection standard of the hottest printin

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Briefly describe the quality inspection standard of printing film

the output of film is actually an exposure process similar to photography. It first converts the dot matrix image (that is, the picture and text are composed of points) processed by rip, and then converts it into the signal dominating the laser. Using the longitudinal and transverse movement of the laser relative to the film, the laser points (that is, points) are hit (shot) to the corresponding positions of the film, so that the corresponding parts of the film are exposed, Then, through the development and fixing process of the developer, the unexposed part is washed away, and a dot matrix image is formed on the film

as for the quality standard of film, it should mainly include the following four aspects:

first, field density and fog, which are the basis for measuring film quality. Fog refers to the absolute density of the blank film, that is, the density of the blank film measured after the densimeter is absolutely cleared (cleared to the air). The film with fog value =0.03 is excellent, and the film between 0.03 and 0.07 is qualified. The so-called field density refers to the density value of large real plots. Generally, the gray scale provided by the hair and discharge software is too small, and some film films have trachoma, which makes the measured value of field density smaller than the actual value, generally at 3 8 is qualified, but if there is a large field, its density value must be guaranteed to be between 4.0-4.3 to ensure that the color saturation of the print will not make the dark tone levels merge

second, linear value, which is the main factor of film quality. Generally, it should be ensured that the difference between the marked value on the gray scale of the film and the measured value is 2, which is qualified. However, because the general high-precision printing machine has a certain degree of color adjustment, we can ensure the quality of the printed matter as long as we ensure its linearization difference of 5

III. point shape, angle and number of hanging lines. The points should be smooth, solid, without sawtooth and tailing; The angle conforms to the standard (generally, the monochrome is 45 degrees, and the four colors want to be 30 degrees worse), and there is no collision; The number of hanging lines is suitable for printing media (for example, paper is not higher than 120lpi, coated paper is not lower than 1, and the effect ranking method is based on the frequency of vocabulary display of 33lpi)

IV. the quality of the drug film after exposure is the last hurdle, and it is also the most easily ignored factor. There is no trachoma on the film, no scratch on the film, no oil stains, and no white spots that have not been removed by fusing. It can be said to be a film of qualified quality

hanging accuracy

hanging accuracy is generally called hanging accuracy. The higher the hanging accuracy, the more exquisite the printed product is, but it has a great relationship with paper, ink, etc. If you print a high hanging picture on ordinary paper (newspaper), the picture will not become more beautiful, but will become a mess (terrible). Therefore, before output, you must know what the printing paper of your printed matter is, and then decide the hanging accuracy. General common paper and eye accuracy: imported coated paper or self-adhesive, etc.: line; Imported offset paper, etc.: line; Ordinary offset paper, etc.: line; Paper: line, and so on. The worse the paper quality, the lower the hanging eye, and vice versa

paper has strong ink absorption ability. The smaller the point, the stronger the relative expansion. 175 line is smaller than 150 line, so 175 point expansion is a little more serious. Under the same printing conditions, the printed color is darker

high thread does not mean that the quality of the product is high. It is best to use 150 thread for paper! The shape and restoration quality of dots is an important standard to determine whether the printed matter is exquisite! Many coated paper prints abroad will also use 150 lines, with the same exquisite effect

printing point angle

green: 15 degrees, red: 75 degrees, yellow: 90 degrees, black: 45 degrees. Generally, the dots are arranged neatly, so there will be angles in application. For example, in monochrome printing, the line angle is mostly 4 degrees to provide solutions for a series of industrial markets related to personal hygiene, such as automobile, packaging, medical care, household appliances and construction. This is based on the dots printed from this angle, which is the most comfortable visually and is not easy to detect the existence of dots when testing only one material, And cause the effect of continuous gray tone

as for printing with two colors and the maximum cooling temperature of liquid nitrogen can reach ⑴ 96 ℃ or above, we should pay attention to the combination of two angles, otherwise unnecessary patterns will be produced, which is called moier. Generally, if the angle difference between the two is 30 degrees, there will be no collision. Therefore, generally, for two-color printing, 45 degrees will be used for the main color or dark color, 75 degrees will be used for the light color, and 45 degrees, 75 degrees and 15 degrees will be used for the three colors respectively. If it is a four-color printing, 75 degrees will be used for the red color, 90 degrees for the yellow color, 15 degrees for the green color, and 45 degrees for the black color. These perspectives are not limited, but changed according to different needs

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