For the packaging and printing enterprises under the traditional working mode, the final printing quality depends directly on the plate making quality to a great extent. Especially under the current conditions of prepress openness and socialization, there are many informal prepress plate making companies. There are some non-standard problems in the film live parts provided by them, such as printing and post press processing technology are not considered in the design and production.Standardize the prepress production of book printing.
The uneven film quality will affect the production and final product quality of printing enterprises, and some even affect the reputation and economic benefits of printing plants. Therefore, standardizing prepress operation is an urgent problem to be solved. Here, combined with the actual situation of our factory, China Paper Network summarizes the possible problems in foreign film and prepress production.Standardize the prepress production of book printing.
1. Quality problems caused by being unfamiliar with plate making software
Due to incomplete understanding of plate making software, improper operation in the process of use, some quality problems appear. For example, if the printing enterprise gives the scanned image file with the adjusted level to the customer for further production, the customer does not understand the meaning of some options in the software: the wrong option is selected, which makes the adjusted image level beyond recognition, and the color, saturation and level of the print are inconsistent with the original. Finally, the customer is not satisfied with the printing effect, However, it was their own wrong operation that led to such a result.Standardize the prepress production of book printing
Some software has a very good effect in arranging the English version, but there may be some problems in arranging the Chinese version. In the design and production, the operator should try to avoid using some fonts or functions. For example, when using PageMaker for typesetting, punctuation marks will be stuck behind Chinese characters when using some fonts; Some designers choose the bold function when designing fonts, which is very easy to paste words when making films.Standardize the prepress production of book printing
2. The film density of the same product is inconsistent
Some plate making companies do not carry out linear control on the output process, resulting in different or insufficient film density and false dot. When proofing, arrange the films with similar density together, as long as the proofing sheet is approved by the customer, regardless of whether the actual printing can be realized. In the actual printing production, after a book is assembled into a large version, the films with different densities are likely to be arranged in the same version, and some page strokes and lines will appear on the printing plate. Strong, some page text broken strokes, thin lines. Standardize the prepress production of book printing
Such printing plate printing not only brings inconvenience to the operation, but also the ink color of each page can not be guaranteed to be consistent. After binding into a book, it is inevitable that the ink color before and after the whole book is different. Standardize the prepress production of book printing
For high-end color printing materials such as picture albums, due to the inconsistent dot density, the drying version is deep and shallow, so it is difficult to catch up with the proofing effect during printing, and it is difficult for customers to accept the printing samples, resulting in contradictions between customers and printing enterprises.Standardize the prepress production of book printing
3. The screen angle setting of four-color film does not meet the printing requirements
Conventional four-color printing is completed by printing and printing four color separations with screen. In order to prevent the four-color dots from interfering with each other and generating moire, it is usually necessary to set different screen wire angles according to the different characteristics of printed matter. Standardize the prepress production of book printing
For example, for products dominated by characters, the screen wire angles are generally 90 ° for yellow version, 45 ° for magenta version, 75 ° for green version and 15 ° for black version; For products dominated by scenery, the cable angle is generally 90 ° for yellow version, 75 ° for magenta version, 45 ° for green version and 15 ° for black version; For some special products, the black version may also be set to 45 °.Standardize the prepress production of book printing
The setting of screen angle plays an important role in the restoration of printing color. If the screen angle is not set correctly, the picture is prone to color deviation or ugly moire in the printing process. Especially when the printing equipment is worn to a certain extent. When the accuracy is slightly poor, the printing quality can not meet the requirements of the sample. For films provided by plate making companies, the screen angle setting is often not standardized. Standardize the prepress production of book printing
For products mainly focusing on people’s faces, the magenta version is set to 75 ° or 15 °, and sometimes even two films use the same screen angle. As proofing is a wet dry process, printing is a wet wet process, and the equipment conditions are not good. The quality of raw materials is completely different, so there may be no problem setting such a screen angle during proofing, and there may be one or another quality problem during printing.Standardize the prepress production of book printing
4. Printing conditions are not considered in the setting of network cable number
Many plate making companies believe that the higher the number of network cables, the better the quality of products. In fact, it is not. Because the products higher than 200 lines / inch are printed by ordinary printing press, it is impossible to completely restore the full tone dot, there may be merging, and the picture level will be lost.
Therefore, the number of screen lines should be set according to the printing conditions during plate making. According to the current market situation, generally high-grade picture albums and fine products are printed with high-grade four-color machine, 175-200 lines / inch is more suitable; Standardize the prepress production of book printing
General color periodicals (light coated paper printing) can be printed by general four-color machine, 150-175 lines / inch; For monochrome periodicals and books printed on non light coated paper, it can be printed by domestic offset rotary machine, 100-133 lines / inch. In other words, for different printing conditions, it is meaningless to use different screen lines, not one size fits all, and blindly pursue high screen lines.
5. The layout center size is not standard
Due to the lack of printing knowledge of many designers, when designing the layout center, they are more arbitrary, the size of the layout center is different, the head and foundation are not unified, and the page number position is not unified; Some pages have no cutting line; In some pictures, the bleeding place of the color block is not large enough to produce blood after making the finished product; Some pictures should not bleed, and the edge is too close to the finished product line.Standardize the prepress production of book printing
Due to the error of folding and cutting, they become bleeding graphics and text after cutting into the finished product, which not only deviates from the designer’s design intention, but also becomes waste. In addition, the non-standard layout will also bring difficulties to printing production.Standardize the prepress production of book printing
On the one hand, it is not easy to position when making a large version. In order to make the whole book beautiful, it is bound to cut and shift the layout, which increases the workload and difficulty of making a version. On the other hand, due to the cutting and shifting of the layout, it is easy to have various quality problems, such as more dirty lines in the layout, inaccurate drying of lines due to uneven film, etc.Standardize the prepress production of book printing
6. The production of characters and lines is not standardized
Prepress production requires that the ship’s monochrome (black) text, line drawing or bar code should be made into single black, while foreign films are often four-color overprint composite black. Four color black is often difficult to register when printing, and the edges or lines of printed words are not clear. Another situation is that the anti white characters on the three-color or four-color composite background are too small and too thin, which is also prone to inaccurate overprint and fuzzy lines and words. Standardize the prepress production of book printing
These designs that do not meet the printing process requirements not only increase the printing difficulty, but also deviate from the original intention of the designer, affecting the beauty and reading of the product. For the final quality of printed matter, the production before printing must meet the requirements of printing process, and the single black text should be used. Do not use four-color black lines, use bold fonts for anti white characters, and do not use too many colors for the background color of words. The product printed in this way is simple. Bright, clear and generous, and the quality is guaranteed.Standardize the prepress production of book printing
7. Non standard proofing
The proofing of most plate making companies does not meet the printing requirements. When proofing, the plate is light, and the dot of the sample sheet is as large as that of the film. When proofing, increase the amount of ink, and the sample sheet looks bright and thick. When this film is sent to the printing factory, the printing enterprise can’t catch up with the effect of the sample sheet no matter how the ink is piled. Standardize the prepress production of book printing
Because the first color ink is dry and then overprint the second color ink, the ink layer thickness is large and the dot increase is small. The printing equipment runs at high speed, and the ink layer overprint is wet, so the ink layer is thin and the dot increases greatly. Standardize the prepress production of book printing
In view of the differences between the two methods, printing enterprises have different technical requirements for proofing and printing. Usually, when drying the proofing plate, 2% of the outlets are dried out and 3% of the outlets are aligned. When drying the printing plate, 3% of the outlets are required to be dried out, so as to ensure that the printing sample is basically consistent with the proofing sample.Standardize the prepress production of book printing
8. The process requirements of post processes such as binding are not fully considered in prepress production
Binding process is different, plate making is also different. Some films do not consider the binding position when making wireless binding and book edition. After they are packed into finished products, the binding edge cannot be opened, and some pictures and texts are fixed and invisible, affecting the reading of books. The cross page picture and title of the book ordered on horseback are made at the position that is not the center page.
Due to the error of paper thickness and folding, the cross page picture and title will appear high and low dislocation after binding, which will affect the beauty and reading of the book. For wireless binding products, 2-3mm milling back position shall be reserved at the edge of binding; For products ordered by horse riding, it is best to put the cross page on the center page.Standardize the prepress production of book printing
The nonstandard pre press plate making not only restricts the quality of final prints, but also restricts the production cycle. Due to the nonstandard pre press plate making, in order to ensure the final print quality, printing enterprises have to take various means to modify, adjust and test dry the films that do not meet the printing requirements in production. For the problems that can not be solved, they have to let customers take them back for modification or even make them again. Standardize the prepress production of book printing
This not only wastes a lot of human, material and financial resources, but also prolongs the production cycle. Even so, the printed products may still make customers dissatisfied. Therefore, we call on prepress operators to strengthen professional training and experience accumulation, and the perfect combination of standardized prepress operation and prepress digitization, so as to quickly produce high-quality and exquisite prints in line with social needs.Standardize the prepress production of book printing