Corrugated box direct flexographic prepress design analysis (on)

In the past, the main function of corrugated boxes was as a transport package, and the surface printing was also very simple. The reason is as follows: First, the carton factory and users do not attach importance to the packaging design of corrugated boxes, and only use the carton as a tool to protect and dress products; secondly, the surface roughness of corrugated boxes is relatively poor, and it is difficult to print exquisite designs; The previous printing version of the Sichuan version of Xing was a hand-engraved version, and it was impossible to reproduce fine lines and dots. Of course, there are also a few printing units and other reasons, which have limited the rapid development of carton printing.

In recent years, with the rapid economic development and increasing exchanges with foreign countries, people are increasingly aware of the importance of packaging and decorating, especially the rising number of international supermarkets such as Wal-Mart and Carrefour and the increasing number of domestic supermarkets. People have changed the traditional shopping habits. At the same time, the sales function of corrugated cartons has become increasingly prominent. Users have increasingly valued the outermost packaging of cartons, the display products and the company's image. At the same time, the universal application of flexographic printing plates (photosensitive resin plates) and the rise of flexographic prepress technology have also given strong support for carton printing.

In the field of packaging design, past color packaging or beautiful packaging did not count mostly through offset printing and gravure printing. Offset printing and gravure printing are mature printing methods. There is still a lot of printability that designers need to pay attention to when designing packaging. Flexo printing is a new printing method. If you want to truly reproduce the designer's packaging, you don’t need to count. The teacher learned more about the characteristics of flexo. In the prepress design for direct flexo printing of corrugated boxes, designers must pay attention to the following points.

Express the color number of creative ideas

The colorful world, especially the designer’s eyes, is also good at discovering beautiful colors and organizing them organically, creating various types of elegant or elegant, bold or warm, or having a strong visual impact. s work. As a packaging design, the ultimate goal is to achieve its own creative results after printing, and to achieve industrial production. Therefore, for the packaging design of corrugated cartons directly flexo printing, in the use of color, we must first understand their own creativity in a few color printing machine to achieve, clear their own ideas through a few colors to express. The number of domestic corrugated cartons flexo printing presses is generally 2, 3, 4, and 6. Before confirming the use of several colors, the number of sets of printing presses should be taken into consideration. On the other hand, it must be considered from the process whether white ink is used or whether lacquer is used in order to finally determine the number of colors that can be used to express creativity.

Of course, under the premise that the same can fully express the design creativity, the number of printing colors should be reduced as much as possible, which is beneficial for the printing operation, quality control, and cost control in mass production.

In addition, there are also many manufacturers who wish to use as many spot colors as possible in order to achieve the uniform color of each batch of products and to play a certain anti-counterfeiting effect. Thus, in addition to the traditional CMYK4 color, its packaging uses spot color inks. However, in actual operation, due to limitations of printing machines, manuscripts that need to be printed on a four-color machine do not show up in any of the four colors at the time of color separation. In the end, they have to communicate with the designer, and the colors are similar to each other. Or make changes to the designer's work.

Because the flexographic printing is transmitted through the anilox roller, the number of the anilox roller determines the amount of ink transferred and the fineness of printing. In general, the net-tone version uses a high number of anilox rollers to make the dots clear; while the field version uses a low-number anilox roller to achieve color saturation. In a color, there are both halftone images, and on the ground, and when they are visually prominent, this color is generally divided into a halftone edition and a field edition separately to facilitate the printing operation. Therefore, when considering the overall color number in the design process, do not ignore the separation characteristics of flexo printing.

In addition, it is often encountered in practice that many corrugated box printers are three-color machines and cannot achieve normal four-color printing. Therefore, in the process of watermarking a corrugated cardboard box, three colors are often used. Reproduce four-color manuscripts. There are two actual situations to consider when producing black with three-color overprint:

(1) ink color cast to produce non-standard black three-color overprint;
(2) Three-color overprinting can make the ink layer too thick, affecting the printing quality and effect.

For the above two cases, the designer needs to understand the condition of the ink when processing the packaging product printed with the tricolor machine. Some printers use the ink color cast to properly consider reducing the color intensity of the selected color. Some articles may not necessarily remove the black version. For example, the reproduction of the food can eliminate the cyan version, and the reproduction of the tree can remove the red version. This maximizes the original style and hierarchy. If the problem of printing color number is taken into consideration at the time of design, the above difficulties will not be encountered before mass production. For example, when we dealt with the design of Tsingtao beer cartons, we took into consideration the fact that we had to implement it through three-color printing presses. Therefore, the watermark color printing process of corrugated cartons was successfully implemented and was promoted in the market.

Pay attention to the level of application

Because of the different tastes of the designers, the characteristics of the products are different. Therefore, there are differences in the style of packaging design. Some of them are pursuing simplicity and some are rich in pursuit. However, if its design works are achieved through flexographic printing, the use of layers in design must attract the attention of designers.

Because the flexible version is a letterpress, the material is highly flexible and deformable, so the dot gain after press is more serious, and in the process of plate making, 1% or 2% of small dots are easily lost during the printing process, during the printing process. The medium can't be reproduced very well. 3% of outlets will expand to about 10% after printing, and it is impossible to achieve a very soft effect with a gradient of 100% to 0%. Therefore, the level of highlights and shades that can be expressed by flexographic products is relatively small, and those with better printed products can only reproduce 8% to 10% of the dots. Therefore, less than 8% of the dots in the design will not show up in actual printing. Such as the use of gradient color, if the network gradient to 0%, in the small network or to have a clear boundary or seal, thus affecting the packaging image. Although each manufacturer has its own way to overcome or solve this problem, flexo printing cannot match offset printing anyway. This feature of flexo is only taken into account when designing to achieve your design after printing.

Another example is the fact that the edges of the image are dimmed, and if they are dimmed to a net, the aforementioned problems will also arise. This requires the designer to consider avoiding the emergence of such problems in the packaging design.

In addition, as mentioned earlier, the number of anilox roller lines used in flexo-ink transfer is different for halftone and field versions. Large areas are connected to local gradients, and printing is very difficult. In particular, the manuscripts with darker colors in the field take care of the part of the mesh tone, and the actual printing on the ground is not true or the color is light; taking care of the field, the halftones are partially stenciled and have dirty spots. Although it can sometimes be solved by selecting an anilox roller with a moderate number of lines and reducing the number of screen lines in the halftone portion, it is in any case inconsistent with the original intention of the designer.

It is worth mentioning that in packaging design, gold and silver ink are often used to enrich the packaging design and improve the packaging quality. In the use of gold and silver ink, if the pattern contains a halftone, it is best to leave some space in the high light and dark wither, the best light at the best network is more than 20%, because this kind of ink printing dot is easy to paste version.

(to be continued)