Although offset printing has the above excellent characteristics, it still has high technical requirements to print exquisite realistic patterns and multi-color complex artworks. In addition to the printing equipment, printing materials, printing process and the skills of printing operators, the early artwork evaluation and color separation and film production are also crucial to offset printing, such as printing gradient colors, overlapping colors, color block splicing, realistic effects, etc. These have high technical requirements and are prone to large-scale unstable phenomena. Of course, the same artwork will have different printing effects in different factories. There are mainly the following reasons:
(1) Film production:
Why can some factories print the artwork on the tube for the same artwork design, while some directly reply to change the manuscript. This is also a common problem encountered during development. This is usually closely related to the factory's technology, which is what we call the artwork cannot be separated into colors and produced on film. After the factory receives the artwork, the first thing to do is to separate each color into an artwork according to the converted document and then make a film, and then use the film to print the offset plate. However, some patterns in design drawings cannot be converted to curved formats. For example, it is relatively difficult to print pictures on film, and the distortion will be serious. For example, the following hose cannot be converted according to the effect of color separation printing of the picture. In order to achieve a similarity close to the manuscript, it is necessary to go through three or more film modifications. If there is no manuscript but only a sample, you can cut the sample tube and scan the pattern of the sample tube into the computer, and then use the design software (PHOTOSHOP or AI, etc.) to repair and compare the scanned pattern, and produce the film according to the color of the sample tube.
2) Color matching:
Usually, a six-color offset printing machine can print more than six colors of drawings by overlapping colors. If the color of the drawing exceeds the color of the printing machine, the design manuscript must be changed. When printing, the printing master will adjust the same color according to the Pantone number required by the drawing. If there is a color sample, the printing color will be adjusted according to the color sample. If white or light color is offset printed on a colored tube (especially black or dark colored tube), there will be a significant color difference between the printing color and the manuscript. When printing in layers, there will also be color difference problems with the manuscript. In general, in addition to being closely related to color separation, it is mainly related to the printing machinery and printing operators. Printing technicians adjust the color depth according to the ink volume and printing machine pressure of the ink fountain.
For example, the following figure is a difficult layered printing. It is a design drawing with gradient and layered colors, which is also relatively rare in design drawings. Despite multiple adjustments, the film is still different from the original manuscript. Once the customer confirms the sample tube, the customer's later change of factory production increases the difficulty of printing. It is even more difficult to make a sample tube according to the original manuscript because the factory will not send the modified drawings to the customer.
(3) Screen line
When outputting the film, the change of screen line is also used to achieve the printing effect of the manuscript. For example, when printing color blocks, the screen line can be reduced to complete the ink accumulation phenomenon at the joints of color blocks. Usually we use 120lpi in offset printing, but when large color blocks are joined together, 100lpi or lower is used, which will improve the ink accumulation phenomenon.
Offset printing is an important part of hose packaging printing. The packaging quality, product description and brand recognition of hoses are inseparable from printing technology. A hose with beautiful artwork can make the product stand out in the fierce competition.
In short, the hose manufacturing process determines the market foothold of offset printing. For hose printing, offset printing is an indispensable part.
