Overprint plate making method

Abstract

The invention discloses an overprint plate making method, which is characterized by comprising the following steps of: (1) laying out a page; (2) performing color separation; (3) trapping an image; (4) rasterizing the image; and (5) making up. During the trapping of the image in the step (3), the number of lattice point layers of a dark color image and a light color image to be overprinted is changed, and then overprint is performed at an overprint region of the light color image to an overprint region of the dark color image, so that the tone of an overprint image is obviously reduced, the contrast with the dark color image and the light color image before overprint is relieved, the defects of overlaying mark of two-color overprint and accuracy error of a printing machine are overcome, and according to the technical improvement, not only is the product quality guaranteed, but also good economic benefit stands out, the plate printing and printing frequency are saved, and the product quality and the yield are improved.

Description

technical field [0001] The invention relates to a printing method, in particular to an overprinting plate-making method. Background technique [0002] The printing of high-end packaging boxes is generally based on the four-color printing of C, M, Y, and K plus spot color printing. The exposure of the background color of the printing material between the two bottom plates will visually produce a thin white line (ie, leakage) or a third-color overlapping line of two-color overprinting. These defects will seriously affect the appearance of the printed product. However, in the actual production process, due to irresistible factors such as mechanical system errors and printing material deformation, it is impossible to achieve absolute registration between printing plates. In order to solve this problem, different image processing software and typesetting software manufacturers have Some solutions are proposed, and the software is basically designed according to the principle of ...

AI Technical Summary

Problems solved by technology

The existing image processing software mainly solves this problem through the layering method and shifting method, but these image processing software will also have some problems after trapping and cannot meet the high-quality requirements of printed products, such as: 1) AdobePhotoshop The trapping of the image is mainly done by setting the trapping width of the image in CMYK mode. Only by setting the width of the trapping, the image can only be trapped by enlarging the color, which will cause the color block and the color block to be trapped. Broken products and jagged edges appear on the outline boundary, which affects the quality of printed products

2) Adobe Illustrator software mainly sets the width of the trapping area, the ratio of vertical trapping to horizontal trapping, and the reduction ratio of bright tones. Compared with Photoshop, its trapping effect is much better, but its disadvantage is Automatic trapping does not work between fills and strokes, gradients, continuous tone images, and other features

3) Even CorelDraw, which has a high usage rate in domestic packaging and printing factories, cannot realize automatic trapping of continuous tone images and imported images

Professional packaging trapping software such as: PackEdge, Artpro, Esko-Graphics’ Deskpack, Founder’s Packsharp, Heidelberg’s QM DI46-4 and Creo’s Trapwise all require an independent software system to use, which requires users to The software and the trapping module must be purchased at the same time before the trapping module can be used, which undoubtedly greatly increases the financial burden of the user and sets a threshold for the prepress publishing staff

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