Prepress printing for standard book printing

For the printing enterprises in the traditional working mode, the quality of the final printing products largely depends directly on the quality of the plates. In particular, under the current pre-press opening and socialization conditions, many prepress Platemaking company. There are some non-standard issues in the film jobs they provide, such as printing and post-printing processes that are not considered in the design process. The uneven quality of the provided film will affect the production and final product quality of the printing companies. Some of them will even affect the reputation and economic benefits of the printing factories. Therefore, regulating prepress operations is an urgent problem to be solved. Here, the author combines the actual situation of the factory and gives an overview of possible problems in foreign films and prepress production.

1. The quality problems caused by unfamiliar with the plate making software

Due to the incomplete understanding of the plate making software, improper operation during the use process, some quality problems have arisen. For example, if a printing company passes a fine-tuned scanned image file to the customer for further production, the customer does not understand the meaning of certain options in the software: the wrong option is selected, which makes the adjusted image hierarchy unrecognisable and the color of the printed product. Saturation, leveling and manuscripts are contrary to each other. Finally, customers are not satisfied with the printing results. They do not know that their own wrong operation has led to such a result.
Some English versions of the software are very effective, but the Chinese version may have some problems. In the design of the production, the operator should try to avoid the use of certain fonts or features. If using PageMaker typesetting, the use of certain fonts will cause punctuation marks to stick behind the Chinese characters; some designers have chosen to use a bold function when designing fonts, and it is very easy for a character to appear when the film is out.

2. The same product film density is inconsistent

Some plate-making companies did not perform linearization control on the output process, causing the density of the output film to be different or the density to be insufficient. When proofing, then the film with similar density is lined together, as long as the sample proofs are approved by the customer, regardless of whether the actual printing can be achieved. In actual printing production, after a book is published in a large version, films of different densities are likely to be in the same version. The printed version of the printed version will have clear strokes and lines. Solid, some text breaks strokes and thin lines. Such printing on the printing plate not only brings inconvenience to the operation, but also the ink color of each page cannot be guaranteed to be consistent. After binding the book, the shades of ink before and after the entire book are inevitable. For high-end color prints such as photo albums, due to inconsistent dot density, the printed version is very shallow and dark, it is difficult to catch up with the proofing effect when printing, and customers are difficult to accept the print sample, causing customers to conflict with the printing company.

3. Four-color film cable angle setting does not meet the printing requirements

The conventional four-color printing is completed by four screen-printing color separation sheets and printing on the machine. In order to prevent the four-color dots from interfering with each other and generate moire, it is usually necessary to set different cable angles according to the different characteristics of the printed material. For example, for people-oriented products, the cable angle is generally 90° in the yellow version and 45° in the magenta version. Green version 75°, black version 15°; for landscape-oriented products, the cable angle is generally yellow 90°, magenta 75°, cyan 45°, black 15°; for some special products, also It is possible to set the black version to 45°.

The setting of the network line angle plays an important role in the printing color reproduction. If the network line angle is not set correctly, the picture may be easily colored or produce an unsightly moiré pattern during the printing process. Especially when the printing equipment has a certain degree of wear. When the accuracy is slightly poor, the quality of the printed product basically fails to meet the proof requirements. However, the film provided by the plate-making company is often subject to the situation that the angle of the cable is not standardized. For products whose faces are people's faces, the magenta version is set to 75° or 15°. Sometimes there are even two films with the same screen angle. . Since the proofing is a wet-stacked process, the printing is a wet, wet process and equipment conditions. The quality of the raw materials is completely different. Therefore, it may be no problem to set such a screen angle when proofing, and there may be such or such a quality problem when printing.

4. The number of screen lines is set regardless of the printing conditions

Many plate-making companies believe that the higher the number of network cables, the better the quality of the products. This is not the case. Because products with more than 200 lines/inch can't completely restore full-tone dots after printing by ordinary printers, the parallel level may occur, and the level of the picture may be lost. Therefore, the number of screen lines must be set according to the printing conditions when making the plate. As for the current market, general high-end albums and fine products are printed with high-end four-color machines, and 175-200 lines/inch are more appropriate; general color periodicals (printed with light-laid paper) are printed with common four-color machines, 150-1. 75 lines / inch can be; and for non-light coated paper printing monochrome journals and books and products, using domestic offset printing rotary printing, 100-133 lines / inch can be. In other words, for different printing conditions, different screening lines are used, and it is not meaningful to pursue high screen lines blindly.

5. Edition heart size is not standardized

Due to the lack of printing knowledge of many designers, in the design of the heart, the randomness is greater, the size of the mind is different, the sky is not uniform, the foot is not uniform, the page position is not uniform; some layout has no cutting line; some pictures, color The place where the bleeding was done was not big enough, and blood was not produced after the finished product was finished; some pictures should not be bleeding, and the edges were too close to the finished product line. Due to errors in folding and cutting, the finished product was cut into finished products. Bleeding graphics not only deviated from the designer's design intent, but even became a waste product. In addition, the non-standard layout will also bring difficulties to print production. On the one hand, it is not easy to position large prints. For the sake of the beauty of the entire book, it is necessary to shift the layout of the layout. This increases the workload and difficulty of the imposition. On the other hand, it is easy to displace the layout. There have been various quality problems, such as more dirty lines on the layout, and problems such as unreal lines due to irregularities in the film when printing.

6. Text, line production is not standardized

Prepress production requires that the monochrome (black) text, line drawings, or bar codes of the Chinese version are only black, while foreign films are often compound blacks with four-color overprint. Four-color black is often not easy to register when printing, and the printed text or lines are not clear. Another situation is that the anti-white characters on the three- or four-color compound background are too small and too thin. It is also prone to overprinting, lines, and text blurring. These designs that do not meet the requirements of the printing process not only increase the difficulty of printing, but also deviate from the designer's original intention, affecting the aesthetics and reading of the product. For the final quality of prints, the prepress production must meet the requirements of the printing process, using a single black text. Lines do not use four-color black, anti-white characters should use thicker stroke fonts, text background color do not use too much color synthesis. The product printed in this way is simple. Bright, clear, generous and quality assured.

7. Proofing is not standardized

Most proofing company's proofing does not meet the printing requirements. The proofs will be lighter when the proofs are printed, the proofs will be as large as the film's dots, and the proof will be enlarged. The proofs will look bright and thick, and the film will be sent to the printing house. The printing company will normally print and print. No matter how the pile of ink can not keep up with proofs. Proofing is due to the fact that the ink of the first color is dried and then the second ink is overprinted. Therefore, the thickness of the ink layer is larger and the dot gain is smaller. The printing equipment runs at a high speed and the ink stacking method is wet and wet, so the ink layer is thinner and the dot gain is larger. For the differences between these two methods, printing companies have different technical requirements for proofing and printing. Usually, the pattern is sun-dried. 2% of the meshes are sun dried and 3% of the meshes are out of stock. The printing version requires 3% of the mesh to be dried out. This ensures that the printing samples and the proofs are basically the same.

8. Pre-press production does not fully consider the process requirements of post-processing such as binding

Different binding processes, plate making is also different. Some films did not consider the binding position when they did the binding and bookbinding. After loading the finished product, they couldn't open the mouth, and some of the images and texts were indefinitely invisible and affected the reading of books. Saddle-stitched books make cross-page pictures and titles in places other than the center page. Due to the paper thickness and folding error, cross-page pictures and titles will appear misaligned after binding, affecting the appearance and reading of books. For the perfect binding product, a 2-3mm milling back is reserved for the mouth; for saddle-stitched products, the spread is best placed on the center page.

The non-standard pre-press plateau not only restricts the quality of the final printed product, but also restricts the production cycle. Due to the non-standard prepress plate making, printing companies have to adopt various means to modify, adjust, and test the films that do not meet the printing requirements in order to guarantee the quality of the final printing product. The problem that cannot be solved can only be solved by the customer. Take it back to modify it and even remake it. This not only wastes a lot of manpower, material resources and financial resources, but also prolongs the production cycle. Even so, the printed products may still be unsatisfactory to customers. Therefore, we appeal to prepress workers to strengthen professional training and experience accumulation, and to standardize the perfect combination of prepress operations and prepress digitalization, so as to produce high-quality, socially-accurate and fine print products quickly and efficiently.

Reprinted from: Ke Yin Network

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