Prepress Plate Printing Mistakes (Part 1)

Film is a medium for printing plates, and it is also one of the important conditions that affect the quality of manuscript reproduction. Only the film orientation of the film is correct during the printing process to ensure that the density of the copied graphic is consistent with that of the film, so that the fine dots, lines, and text are clearly printed, which meets the requirements of the product's printing quality. However, if the film film is facing upwards due to an error in the film output or manual imposition, the film does not directly contact the plate. Because the transparent film base has a certain thickness, when the printing plate is exposed, the dots , Small lines and text layout edge, it is prone to a slight amount of light transmission, when the plate can not faithfully reproduce the quality of the original, resulting in reduced density of the printing plate graphic, printing, printing, the phenomenon of the phenomenon appears too light. Therefore, in the film output and artificial make-up, we must pay attention to film direction of the film.

Solutions for printing quality problems caused by prepress plate making mistakes

Once, due to the sporadic film provided by the customer, the output was set incorrectly so that the direction of the film was upward, and the imposition personnel did not carefully examine and correctly identify the direction of the film. After the artificial imposition, the film was delivered to the next process. In this way, due to the lack of quality control experience of the operator, after the four-color printing of semi-finished products, the printed dot color of 20% of the blue flat screen surface is obviously pale, and the entire printed sheet is obviously lacking in comparison with the original. When semi-finished products are tested, they are judged as non-conforming products. After careful analysis of the printed semi-finished products, a remedial solution was developed. The specific approach is: The field lines and text layout in the printing plate will be repaired with the revised solution, leaving only 20% of the flat screen printing machine to register and printing again. This way, the C color will be printed after a partial layout The semi-finished product, the overall layout of the printing color that is close to the original, remedial solutions to obtain a successful process effect, the quality of the product has been recognized by customers, to avoid economic losses.

Technical Analysis of Print Quality Problems Caused by Misdirection of Film Film

The above-mentioned printing quality problems caused by the misdirection of the film of the film have exposed the outstanding problems from the prepress production to several printing processes. The first is that the electronic output production staff is not working enough or is not well aware of the exposure process, and there is a certain degree of blindness in the production of flat screens. Second, there are errors in the way the imposition personnel check the film, and it is often used when making impositions. To simply determine the film surface of the film (that is, the direction of the film in general) by simply referring to the text direction of the layout; third, the printing process did not promptly check and find the film error; fourth, the printing process was adjusting the amount of ink. At the time of satisfying the fact that the field lines and text layout were saturated with ink, the plates were not dirty, and the color of the flat screen surface was still pale, the quality of the plates was inspected and recognized, resulting in blind printing. The above-mentioned print quality problems occur.

The correct understanding of the composition of film

The general film film is composed of a film base and a photosensitive film, wherein a transparent film base is used to support the photosensitive film, and the photosensitive film is a chemical emulsion coating layer composed of some photosensitive crystal particles. . The film on the film can only see its particles under the microscope. The imaging principle of film is that the crystal particles on the film will change its structure after being exposed to light and combine with other crystals to form a block. The more light is projected on the film film, the more crystals change and the blocks become more. Therefore, different lights shining on the film will produce crystals of different numbers and sizes and shapes, thus forming an image that has not yet been seen, and the development of the film can transform the latent images on the film into stereotypes. Visible image. The production process shows that the density of the film on the film is higher on the photosensitive part, and the density of the film on the less sensitive part of the image is small, while the part without the light is completely transparent. Generally, the development time of the film is long, and the film of the film is correspondingly thick. On the contrary, the film of the film is thin, which is the basic feature of the film production process.

Film film direction identification method

For the prepress production and inspection personnel, identifying the orientation of the film is the basic skill that must be mastered. Only by doing a good job can they effectively reduce or avoid mistakes in work and ensure the quality of production.