Description of printing parameters of the hottest

2022-08-16
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Snap -- description of paper advertisement printing parameters (IV)

preparation of manuscript when the common original or valve tip and hole are not tightly closed

although the application of digital documents in cold set printing process is growing rapidly, some common documents, such as paper and film, are still used. The following are some guidelines for preparing ordinary materials:

photographic pre reflective originals

when preparing pre reflective originals for printers and newspapers (such as adding photos, positive pictures of photo paper and other reflective drafts), the following guidelines should be followed:

it is recommended to use the sample number N line manuscript that is definitely suitable for black and white to get the best effect, and the red on the black background will produce inferior quality

originals with light lines will not be well copied, such as pencil drawings and charcoal paintings, so it is not recommended to use such originals

the manuscript submitted in the final size will get the best reproduction effect, and frequent enlargement or reduction of the manuscript will lead to the loss of details

the final size must be met when submitting the pre added original, because zooming in or out will change the effect of tone reproduction

when outputting font manuscript, line manuscript, photos and other hard copy materials, the output resolution should be 1200dpi

the font manuscript, line manuscript, photos and other hard copy materials must have a uniform minimum maximum density Dmax (1.7), and a stable Dmax between 1.7 and 1.9 will help to improve the replication effect

photocopied or faxed materials cannot be submitted as duplicate originals, and a series of subsequent continuous processing will reduce the printing quality, resulting in the decomposition of lines and words

target value of tone copy

considering point enlargement/tvi, for images with photos and images that will be copied as black-and-white or monochrome halftone, use the target value of tone copy in the following table

tone reproduction target value obtained by using the line camera

tone area - line camera offset printing (DPI) flexo printing (85lpi) embossing (LPI)

polishing/no detail 0% 0% 0%

highlight 10% 15% 15%

quarter tone 20% 20% 20%

middle tone 38% 38%

dark tone 80% 80%

note: the line camera will increase the contrast of the original. When making a line draft with photos, it is common to lose 10% of the high light tone and increase 10% of the dark tone. The values in the chart are calculated by Yule Nielsen formula (n is assigned 1.7)

tone copy target value obtained by using the dot copy scanner

tone area (scanner) offset (DPI) flexo (85lpi) emboss (LPI)

polishing/no detail 0% 0% 0%

highlight 5% 7% 8%

quarter tone 22% 18% 18%

middle tone 35% 38% 36%

dark tone 85% 85%

note: when using the dot copy scanner, The highlight part of the gradient curve to the quarter of the gradient will usually lose 2% to 3% points. The values in the chart are calculated by Yule Nielsen formula (the value assigned to n is 1.7)

prepare the film

in order to obtain the best reproduction effect, ensure that the film provided meets the parameter requirements in the printing process. If these parameters are not met, all factors involved in the process will need to be discussed, otherwise it will cause time delay and cost increase

the following are some reference guides:

the film provided must be clean, free of pinholes, scratches, and have good internal and external registration ability

before releasing the film, check the format requirements with the printer or newspaper office, such as whether the film is in a single page form or the format size of the printer

the supplier should discuss with the printer or newspaper whether the film needs punching. If necessary, printers and newspapers should recommend the shape of film punching

the supplier should confirm the correct film image size with the printer or newspaper office, including the page margin and bleeding size

suppliers should work with printers or newspapers to determine the direction of film emulsion layer

determine all uncertainties before submitting the film. Discuss with the printer or newspaper in advance the films that need special treatment

in order to get the best flexibility and reduce the cost of last-minute changes, advertisers may want to put black text on a separate film. In most cases, printers or newspapers always use the printing plate of four-color color separations to print this black text. Therefore, all parties should discuss in advance whether this should be done before issuing the fifth film for black font

criteria for minimum film density Dmin:

☆ Dmin in the following table refers to the film itself. The Dmin of peeling cellulose acetate or other transparent film base will be higher

That is, the cupping value of the plate

☆ in order to obtain the best exposure stability and quality of the printing plate, the operator should not mix the films with a large difference in Dmin

☆ the Dmin value in the following table belongs to the film with a thickness of 0.004 inch. Generally, the film with a larger thickness has a higher minimum density

the following two tables provide the physical requirements for film in cold set printing process

requirements for ordinary film:

film features offset printing, flexographic printing, embossing

minimum substrate thickness/type 0.004 inch polyester substrate

polar negative film

the maximum density is usually 3.8 or a little higher, unless other aspects meet (UV or positive film)

minimum density 0.10 or a little lower (UV), 0.05 or a little lower

point hardness the hard point with the smallest edge

transparency should be minimized, And only the base of the film has transparency

plus angle. The plus angle difference between green, magenta and black is 30 degrees, while the difference between yellow and these three colors is 15 degrees. In any case, the angle of black must be 90 degrees

registration mark each film must have a central registration mark, which is 0.25 inches long and at least 0.250 inches away from the graphic area

cutting mark each film must have a cutting mark at the corner, at least 0.250 inches away from the graphic area, to indicate the final cutting and folding size

identification information each film must include identification information such as color and version, For example: the bleeding area where the page number

exceeds the graphic area (Note: in offset printing and embossing, printing without three side cutting does not need bleeding, for example:) there is at least 0.25 inch bleeding on each side of the page that needs bleeding. Only after consulting the printer or newspaper office can the smaller bleeding size be adopted, and the bleeding map can only contain less important graphic areas

the area of the bleeding chart (the annotation is the same as above) the graphic part on the bleeding page, including text, page number and important images, shall not exceed the final print size by 0.375 inches in any direction

margins/borders the margins around the page must be kept at 0.5 inches, and smaller margins can be used only after consultation with the printer or newspaper office

output resolution of four-color or half tone films. Films printed in four-color, monochrome and two-color must have a minimum output resolution

film output resolution of mechanical or monochrome line manuscript the film of mechanical or monochrome line manuscript must have a minimum output resolution

film requirements of special process:

film characteristics offset flexo embossing

direction (emulsion layer down) positive reading emulsion layer down (rred) wrong reading emulsion layer down (wred) wred

point shape circular (best) circular (best) circular (best) circular (best)

the number of wires added is 85lpi to 100lpi. A higher number of wires added is 85lpi to 100 after consulting the printer or newspaper. If LPI is connected to aluminum alloy cable, The higher number of lines can be used only after consulting the printer or newspaper office. The higher number of lines can be used only after consulting the printer or newspaper office

the overall overprint rate of the image trapping image is 0.001 inch, the overall overprint rate of the image is 0.015 inch, and the overall overprint rate of the image is 0.015 inch

the image that needs strict registration should be avoided across the seam. Strict registration refers to the range of 0.125 inch or less. Images that can cross the seam should be avoided if they need strict registration. Strict registration refers to the range of 0.125 inch or less

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