Briefly introduce indentation and bleeding in printing
It is often said that seven-point plate making and three-point printing can make the finishing point of printing by skillfully using some skills in the process of plate making. Therefore, if you want to be an excellent designer and platemaker, you must be very familiar with the whole printing process, so that you can make a printing plate that meets all kinds of original copy requirements, and finally realize the loyalty of printing to original copy.
Whether it is offset printing, flexo printing, gravure printing or screen printing, obtaining rich colors cannot be realized by a single color. Many colors can be restored by more than two colors.
Below, the author talks about the application of indentation and bleeding in the process of plate making from specific examples for reference of peers.
First, indentation technology Indentation technology means that for two-color or multi-color superimposed pictures and texts, according to the actual situation, according to the color separation order, the printing plate of the previous color plate is slightly indented on the basis of the original size, so as to facilitate accurate overprinting during printing and make the pictures and texts more realistic. For example, the “China Environmental Protection” mark on various packaging materials in the market at present is printed in blue, yellow and gold. In actual printing, many printed products are difficult to be delivered to users due to inaccurate overprinting when green and yellow are superimposed into green, resulting in great losses. Some people think that spot color green can be used to solve this problem. However, whether the spot color green can be increased or not depends on whether the printing equipment of the enterprise has enough color groups to realize this process. What if all the color groups of four-color, six-color, eight-color or even ten-color printing machines are full? In addition, each additional color has at least two disadvantages: First, the cost increases; Second, it makes printing operation more difficult.
In this case, it is a good method to apply indentation technology in plate making. When making plate, the yellow version or green version will be indented, and the problem of inaccurate overprinting will be easily solved.
In addition, at present, the characters on many packages are also overprinted by multiple colors. According to common sense, text color separation overprinting is not recommended. According to the data, the error of image overprinting in color printing is less than 3mm, which is not obvious to human eyes. When the error of text overprinting is about 0.1mm, the human eye can easily detect it. However, in some occasions, in order to highlight a certain artistic effect of characters, color separation overprinting must be adopted, and indentation technology can be adopted in plate making to reduce printing difficulty.
Second, the bleeding technology Bleeding technology means that in order to ensure the stability of the original design size in post-press processing, some color plates are expanded outward by a certain proportion in the original design size according to the actual situation. Modern packaging materials are not only printed by a single way, but also go through many processes from printed products to finished products, such as compounding and bagging in flexible packaging, glazing, laminating and die cutting in paper packaging, etc. These processes may lead to large errors between the design size and the actual size. Therefore, it is necessary to apply bleeding technology reasonably according to different designs. For example, the main color of many flexible packages is full edition. In order to ensure the stability of basic dimensions in the process of compounding, cutting and bag making, the main color plates are expanded outward by 1.5 ~ 3 mm during electric carving, so as to ensure that the finished products meet the requirements.
There are still many technologies in the process of plate making, such as trapping and increment, etc. If they can be applied flexibly, it will be easier to realize faithful reproduction of original documents and make customers more satisfied.