On the most popular printing screening process 0

Printing processing art talk

17. Points increase

as the step value increases, there are more and more ideas. Each dot is kept separate from its neighbors until they are forced to join. By calculating the percentage representation of the gauge distance, all printing dots are separated to avoid accumulation when the density is lower than the intermediate density. Completely random patterns will get random and unwanted accumulation. At higher density levels, several points are connected together at one time. Because the FM screen has no abrupt connection in all specific tones, the tone change is smoother than the AM screen

18. The size of the laser point of the picture and text recorder with point size

3600dpi is 7 μ m. 2400dpi dot size is 10.5 μ m. These two ideas make up 2 × 2 grids are respectively composed of 14 μ M and 21 μ Basic printing ideas of M

one 14 μ The size of M dots is about 1% of the size of 200 lines/inch screen, a 21 μ The size of the dot of M is 1% of the size of 133 lines/inch screen. The development conditions will affect the actual configuration on the film: three basic configurations of intellectualization: the size of the host computer, microcomputer, and printer point. The point size used by some manufacturers reaches 70 μ m。

19. Output time

although FM plus calculation is more complex than am plus calculation, smaller file storage can offset the increased processing time. It can use the resolution of graphic recorder lower than that of conventional screen, resulting in faster output speed, that is, it can get images equivalent to higher resolution with lower resolution output. This is likely to be a reduction in processing time, although the results will be based on specific production realities

20. FM, traditional screen and text are on the same page

many manufacturers publicize the ability to raster process two types of images on the same page. This ability to rasterize traditional and FM screens in different parts of the same page is provided by raster image processor (RIP) manufacturers. Postscript level has the ability to use multiple addition algorithms on the same page

when the resolution reaches about 1000dpi, the text imaged electronically begins to look good. If the resolution of the image recorder below this threshold is used to image on the page, whether the image is added in a random or traditional way, the text looks more or less jagged

21. scanning resolution and positioning accuracy of graphic recorder

in traditional addition, the simple rule is: when the printing machine prints 256 levels of color, the resolution of graphic recorder should be 10 ~ 16 times of the number of lines. In a random manner, 8-bit image data can always produce 256 gray levels, regardless of the resolution of the graphic recorder

22. Film characteristics

high contrast film is key to suppress dot expansion, because there may be some exposure areas around small frequency modulation points. All films will have some partially exposed transition areas around the fully exposed points, which will cause the point size to become larger. The frequency modulation point is very small, and its slight expansion will cause significant effects. Using high contrast film can reduce the area of partial exposure, thereby reducing the potential factor of midpoint expansion at this stage of the process

due to the small tolerance inherent in the FM replication process, the film with the widest exposure range can get the best point replication

23. Traditional process control

the tiny size of the basic printing point expands all the defects in the current proofing technology. The tolerance is usually smaller, and dust and dirt will cause little problems in the AM plus process, but will cause great problems in the FM plus process. The proofing area must be kept clean to avoid fine particles during replication. When the whole system uses small size points, small dust particles will cause defects that cannot be ignored. The printing dots in FM are equal to or less than the dust in am. In the traditional way, overexposure of the printing plate can eliminate them

a consistent and uniform vacuum pressure is required to ensure the consistency between plates and the whole plate. A slight change in vacuum pressure will produce hotspots, which are more noticeable than the same hotspots obtained in amplitude modulation

24. The midpoint of electronic proofing means that the proofing of accurately copying FM dots only needs to show the theme moire existing in the image. The observer judges the final printed image product under the normal reading distance. Therefore, if proofing only represents the appearance of the final printed product, it does not need to point

25. Plate resolution

for printing 14 ~ 25 μ For high-resolution points within m, the printing plate must be able to analyze 4 ~ 6 μ M. When the printing plate is exposed, it must be able to reproduce 6 ~ 8 correctly μ M signal bar, which is of great significance especially for the research and development of lightweight products, to accurately reproduce the smallest point

the microwire signal bar should be used to determine the plate resolution. The resolution of the printing plate is determined by finding the signal bars that look the same in the Yin and Yang parts. If 8 μ If the signal bars of the negative and positive lines of m have the same thickness, the resolution of the printing plate is 8 μ m。

the printing plate must be able to reproduce a single frequency modulation point of the highlight and dark part. If a single point is lost, all details in the 0% - 20% and 80% - 100% areas may be lost. (the hue of these areas is completely reproduced by a single dot spread at an appropriate distance.) According to the traditional standard, in order to correctly reproduce the points of the highlight and dark part, it is necessary to reduce the exposure of the printing plate according to the conventional standard. Reducing exposure may reduce the life of the printing plate and increase the dirty spots of replication

post use exposure processing makes the dots solid to increase the service life of the printing plate. In order to prevent dirty spots on the copy plate, it is necessary to pay attention to the cleanliness of the plate. In order to reduce the variable factors in the printing process, a high-quality printing machine is needed, and poor printing opportunities produce hot spots, resulting in uneven exposure between the whole printing plate and the printing plate. Rough surface plates can improve the degree of adsorption, but may sacrifice the resolution. (to be continued)

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