CN108621534B - Method for detecting screen collision before mixed printing platemaking with different resolutions - Google Patents

Abstract

The invention discloses a method for detecting screen collision before mixed printing platemaking with different resolutions, which comprises the following steps: A. carrying out RIP processing on the design draft twice at different resolutions to respectively obtain a first RIP output file packet with a first resolution characteristic and a second RIP output file packet with a second resolution characteristic; the design manuscript requires CMYK to be printed at a first resolution ratio during printing, and a ground color adopts a spot color and is printed at a second resolution ratio; B. selecting and combining RIP output files of CMYK colors in the first RIP output file packet and RIP output files of spot color in the second RIP output file packet to form a third RIP output file packet; C. and (5) carrying out digital proofing by using a third RIP output file package, and observing whether the digital proofing has a network collision phenomenon. The invention can realize the detection of whether the screen collision phenomenon exists in the mixed printing with different resolutions in a digital proofing mode.

Description

Method for detecting screen collision before mixed printing platemaking with different resolutions

Technical Field

The invention belongs to the technical field of printing, and relates to a method for detecting screen collision before mixed printing platemaking with different resolutions.

Background

The pre-press use screening angles for a flexo product in actual printing are as follows: CMYK takes flexo printing conventional screening angles: c: 67.5 °, M: 37.5 °, Y: 82.5 °, K: 7.5 degrees; purple background (spot color purple as background color) and K are at the same angle: 7.5 degrees and the number of platemaking lines is 100L. The real dot is adopted to simulate the output precision of 2540dpi of a common CDI plate, the digital sample is printed to simulate that the flexo printing dots are normal without collision, and the digital sample is shown in figure 1.

The digital sample is output at the resolution of 2540dpi (C: 67.5 degrees, M: 37.5 degrees, Y: 82.5 degrees, K: 7.5 degrees, purple background: 7.5 degrees) without problems; however, the feedback in the actual printing sample has moire pattern hitting and net pattern phenomenon in the blending area of CMYK and purple base, as shown in FIG. 2 and FIG. 3. Why do this happen?

The technical field personnel all know that the current mainstream flexographic plate making is divided into the coexistence mode of the traditional common CDI and the flat-top screening plate making, wherein:

1. the output precision of the ordinary CDI plate is 2540 dpi;

2. the output precision of physical screening of the Kodak flat-top plate making is 2400 dpi;

3. the screening output precision of the front end of the esko flat top printing is 4000 dpi;

4. the eraser physical screening output precision is 5080 dpi.

In the above printing sample, CMYK adopts 2540dpi ordinary fullinate plate material screening plate making using ordinary CDI, and the special violet net adopts dupont P + flat top 4000dpi resolution plate making alone, and after verifying the rip plate making file of plate making factory, it is verified that: the occurrence of the above moire phenomenon in actual printing is caused by the mixture of different plate-making output resolutions 2540dpi and 4000 dpi. However, the existing digital samples are all output with the same precision, so that the phenomenon of net collision cannot be detected.

Disclosure of Invention

The invention aims to solve the technical problem of providing a screen collision detection method before mixed printing platemaking with different resolutions, which can detect whether the screen collision phenomenon exists in mixed printing with different resolutions by a digital proofing mode so as to overcome the defects in the prior art.

In order to solve the technical problems, the invention adopts the following technical scheme:

a method for detecting screen collision before mixed printing platemaking with different resolutions is characterized in that:

A. carrying out RIP processing on the design draft twice at different resolutions to respectively obtain a first RIP output file packet with a first resolution characteristic and a second RIP output file packet with a second resolution characteristic; the design manuscript requires CMYK to be printed at a first resolution ratio during printing, and a ground color adopts a spot color and is printed at a second resolution ratio;

B. selecting and combining RIP output files of CMYK colors in the first RIP output file packet and RIP output files of spot color in the second RIP output file packet to form a third RIP output file packet;

C. and (5) carrying out digital proofing by using a third RIP output file package, and observing whether the digital proofing has a network collision phenomenon.

By adopting the technical scheme, whether the net collision phenomenon exists in the mixed printing with different resolutions can be detected in a digital proofing mode, so that whether the printed matter has the net collision problem can be judged in advance with extremely low cost, the generation of defective products is avoided, and the quality of the printed matter is improved.

Drawings

FIG. 1 is a digital sample obtained by prior art digital printing;

FIG. 2 is a print sample obtained by printing;

FIG. 3 is an enlarged partial schematic view of a print sample;

FIG. 4 is a diagram illustrating RIP output with selected resolution;

FIG. 5 is a schematic diagram of a first RIP output file package including RIP output files of various colors;

FIG. 6 is a schematic diagram of a second RIP output package containing RIP output files of various colors;

FIG. 7 is a schematic diagram of a third RIP output package containing RIP output files of various colors;

figure 8 is a digital sample obtained by the method of the invention.

Detailed Description

The design draft of this embodiment is also screened using the following angles before printing: CMYK takes flexo printing conventional screening angles: c: 67.5 °, M: 37.5 °, Y: 82.5 °, K: 7.5 degrees; purple background (spot color purple as background color) and K are at the same angle: 7.5 degrees and the number of platemaking lines is 100L.

Carrying out RIP processing on the design draft twice, wherein the resolution of the RIP processing for the first time is 2540dpi, and obtaining a first RIP output file packet; the resolution of the second RIP process is 4000dpi, and a second RIP output file package is obtained.

And selecting and taking out RIP output files (with the resolution of 2540dpi) of CMYK colors of the first RIP output file package and RIP output files (with the resolution of 4000dpi) of the purple background in the second RIP output file package, and putting the RIP output files into a new file package to be combined into a third RIP output file package.

And (5) carrying out digital proofing by using a third RIP output file package, and observing whether the digital proofing has a network collision phenomenon. As shown in fig. 8, the digital sample also shows a net collision phenomenon in the mixing area.

Through detailed description, the invention can detect whether the screen collision phenomenon exists in mixed printing with different resolutions in a digital proofing mode, thereby judging whether the printed matter has the screen collision problem in advance with extremely low cost, avoiding the generation of defective products and being beneficial to improving the quality of the printed matter.

However, those skilled in the art should realize that the above embodiments are illustrative only and not limiting to the present invention, and that changes and modifications to the above described embodiments are within the scope of the appended claims.

Claims (1)

1. A method for detecting screen collision before mixed printing platemaking with different resolutions is characterized in that:

A. carrying out RIP processing on the design draft twice at different resolutions to respectively obtain a first RIP output file packet with a first resolution characteristic and a second RIP output file packet with a second resolution characteristic; the design manuscript requires CMYK to be printed at a first resolution ratio during printing, and a ground color adopts a spot color and is printed at a second resolution ratio;

B. selecting and combining RIP output files of CMYK colors in the first RIP output file packet and RIP output files of spot color in the second RIP output file packet to form a third RIP output file packet;

C. and (5) carrying out digital proofing by using a third RIP output file package, and observing whether the digital proofing has a network collision phenomenon.

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