A Printing Remedy For Prepress Errors in Hardcover Books

A printing remedy for prepress errors in Hardcover Books

 

Film is the medium of printing and plate making, and also one of the important conditions affecting the reproduction quality of the original manuscript. Only when the film film direction is correct, can we ensure that the copy of the layout graphic density is consistent with the film, so that the small layout of the dot, line, text and other parts of the printing clear, meet the requirements of product printing quality.

 

However, if the film output or manual plate errors, so that when printing film film direction up, the film does not directly contact with the plate, because the transparent film base has a certain thickness, when printing plate exposure, dot, small lines and text layout edge, it is easy to appear trace light transmission phenomenon, plate can not faithfully reproduce the quality of the original. Resulting in plate graphic density decrease, printing imprinting appears faint phenomenon. Therefore, brochure design template, in the film output and manual plate, we must pay attention to the film film direction.

 

Solutions to printing quality problems caused by errors in prepress platemaking. Once, due to sporadic film provided by the customer, the direction of the film was set incorrectly during output, so that the direction of the film was up. The beverage bottle, and the platemaking staff did not carefully check and correctly identify the direction of the film, the film was delivered to the next process after manual platemaking. When printing in this way, due to the lack of quality control experience of the operator, after four-color printing of semi-finished products, the dot printing color of 20% of the blue flat screen layout appears obvious pale phenomenon. The color blue phase of the whole printing sheet is obviously insufficient compared with the original manuscript, and the semi-finished products are judged to be unqualified products when inspecting.

 

After careful analysis of the printed semi-finished product, a remedial solution was developed. Specific measures are as follows: The field lines and text layout in the printing plate are repaired with the retouching solution, and only 20% of the flat screen layout is left on the machine alignment and printed again. In this way, the printing color of the whole layout is close to the original manuscript after the partial page reprinting. The remedial solution has achieved successful process effect, the product quality has been recognized by the customer, and economic loss has been avoided.

 

Technical Analysis of the printing quality Problems caused by the wrong direction of film film the above printing quality problems caused by the wrong direction of film exposed the prepress production to the printing process there are more prominent problems.

 

One is the electronic output production staff work is not serious enough or not enough understanding of the printing and exposure process, there is a certain blindness to the production of flat net;

Second, there is a mistake in the way of examination of the film. When assembling, the film is often used to determine the film surface (that is, the direction of the film) by simply relying on the direction of the text in the layout;

Third, the printing process did not timely check and find the film error problem;

Four is the printing process in the adjustment of the amount of ink, in order to meet the field line, text layout inking saturation, not dirty version, not paste version, flat screen layout color is still obviously light, ignore the quality of the printing plate inspection and recognition, blind printing and caused the above printing quality problems.

 

General film film is composed of a substrate and a sensitive film, the transparent substrate is used to support the sensitive film, sensitive film is an emulsion coating layer of chemical substances, they are composed of some sensitive crystal particles. The film has particles that can only be seen under a microscope.

 

The way film works is that when exposed to light, the crystal particles on the film change their structure and combine with other crystals to form clumps. The more light is cast on the film, the more clumps the crystals change and form. Therefore, different light shining on the film will produce different number, size, shape and structure of the crystal, so as to form an image that has not yet been seen, and then through development processing can transform the potential image on the film into a fixed, visible image.

 

The production process shows that the density of film on the image of the sensitive part of the film is high, the density of film on the image of the less sensitive part is small, and the part without sensitive is completely transparent. Generally speaking, if the film develops for a long time, the film film will be thick, whereas the film film will be thin, which is the basic characteristic of the film production process effect.

 

For the production and inspection personnel of the prepress process, identifying the direction of the film is a basic skill that must be mastered. Only when it is done well can it effectively reduce or avoid errors in the work and ensure the quality of production.

 

The recognition methods of film film on production site generally include: artificial scraping film recognition and naked eye observation recognition. Artificial scraping film to identify the film surface, is to use blade scraping on the film on the corresponding parts other than the printed product, if the scraping side of the film is damaged, the scratch appears light transmission phenomenon, indicating that the surface is the film surface.

 

The method of identification by naked eye observation is: the film surface is dark, while the non-film surface (base surface) is bright, with obvious mirror effect. If the film is identified by the same piece of screen version, when the film film faces upward for visual inspection, the film has a dim feeling, and the perceived dot density is relatively large, while when the film film faces downward for visual inspection, the film feels bright and glossy, and the dot density is also small.

 

Film dot size identification method if the printing screen version, film film surface does not contact with the plate surface directly, the dot will appear small phenomenon, affecting the quality of product reproduction. Therefore, printing and printing personnel should learn to use the naked eye to identify the common dot. In this way, if the printing plate when the film surface is wrong, resulting in the printing plate dot significantly smaller, by checking the printing plate or printing proof, you can find the printing error.

 

Generally 1~10 percent of the dot is more commonly used, and also easy to identify with the naked eye. The percentage of dots within 5 percent is identified according to the number of particles that can accommodate the same dots in the space between the opposite side of the two dots. That is, in the gap between the two dots on the opposite side, three dots of the same size can be placed, that is, a dot of 1 percent; If in the distance between two dot, can accommodate two of the same size dot, called 2 dot; And in the distance between the two dot, can accommodate 1.5 of the same size dot, called 30 dot; If between the two dots can accommodate l.25 dots of the same size, it is called 4 points; If a dot of the same size can be accommodated between the two dots, that is to say, the unit area of printing dot and white dot accounted for half, is five points. The identification of more than 5 points is measured by how many white points of the same size can be accommodated between the opposite side. From the point of view of the regularity of dot percentage performance, the number of dot accommodated in the spacing of two white points, exactly 6 and 4 are the same; 70% is the same as 30%; 80% is the same as 20%; 90% is the same as 1%. Ten percent of the dot is the field version, fashion T-shirt, if the layout is the field version, because there is no dot gap, there is no oblique transmittance phenomenon, so the field version of the film film up to print, will not affect the field version of the print density.

 

Therefore, a correct understanding of the characteristics of film and several factors affecting the reproduction quality of the printing plate, and careful control of film output, printing process and quality inspection and control technology can not only reduce or avoid the occurrence of quality problems in the pre-press process, but also better guarantee the printing quality of the product.