The Control of Printing Quality of Textbook Illustrations in Primary and Secondary Schools

In recent years, the printing quality of primary and secondary school textbooks has improved significantly with the development of prepress processing, printing, new post-press processing and new technology, and improvement of printed materials. The quality of products of some enterprises has reached Higher standards. However, there are indeed many problems in the illustration quality of textbooks for primary and secondary schools (including art textbooks). Some problems are even more serious and directly affect the use of students. Therefore, it is necessary to comprehensively strengthen quality management from editing, pre-press processing, printing, and post-press processing in order to further improve the overall quality of textbooks. Through the quality supervision and spot checks of textbooks and the detection and identification work of military superiors and high-quality products, the author finds that there are a large number of illustrations with defects such as the loss of tone levels, blurred images, and incomplete image frames, especially in the images. The traces and overprints of the edition are inaccurate, which seriously affects the reading and visual acuity of the students. After analyzing the quality problems of textbook illustrations, it can be seen that the reasons for the poor quality of illustration printing are many, but the main reason is to ignore the meticulous selection of originals and the meticulous design of the layout. In the prepress process management and printing quality control, the lack of specific analysis of the printability of the study, there is no complete set of review standards and technical measures, but also an important reason for the poor quality of the illustrations. The author believes that the current textbook illustrations have the following major problems in terms of editing, prepress, and printing: First, the quality of the original is poor. Under normal circumstances, the use of high-quality manuscripts and the selection of the best technology in the reproduction, the use of good printability, strictly in accordance with standardization, standardization, and data manipulation, can completely obtain high-quality products. However, the manuscripts used in the textbook illustrations are far from manuscripts that are suitable for printing. Even a large number of manuscripts with poor quality are adopted, making it difficult to obtain high-quality products. There are roughly four types of manuscripts used in textbooks: (1) photographic manuscripts (color reversal films, color photographs, etc.); (2) paintings (Chinese paintings, oil paintings, watercolors, etc.); (3) secondary manuscripts (reproduced with photographs, paintings, prints, etc.) (4) Printed manuscripts (prints of different processes, different papers, etc.) The proportion of such manuscripts is rather large, which is one of the important reasons for the poor quality of textbook illustrations. For example, in an art textbook, there is a modern painting called “Jiangshan is so beautiful”. The original manuscript was made from the printed version of the printed version (printed on multiple occasions), and the tone and color of the two parts of the edition are very different. There are still quite obvious traces of connecting plates at the connecting place, which directly affects the artistic appeal and appreciation effect of the picture. Another example is that there is a “Beijing overpass” in a textbook, which is also copied with printed materials. There are about 2mm wide imprints at the joints, dividing a complete bridge into two distinct parts, like “two The bridge "spliced ​​together in one piece, seriously affecting the integrity of the picture, and it is easy to cause misunderstandings to primary and secondary school students. The depth of the illustrations, the rough picture, blurred image, and imaginary halo are closely related to the low quality of the original. Second, the number of mesh lines is not scale. Using high-quality manuscripts, high-precision printing equipment and high-quality raw and auxiliary materials, and under the conditions of the ideal printability, standardized, data-based operations, it is possible to obtain high-quality printing products. Therefore, the selection of the number of mesh lines suitable for textbook illustrations during prepress processing is one of the important steps to stably improve the quality of textbook illustrations. However, we have found from the textbooks that the application of line numbers is not standardized, and it is used from line 80 to line 175. This reflects the random nature of the number of screen lines used in pre-press processing, and the use of screen lines in accordance with printability and paper conditions. This is an important reason for the loss of image tone levels, lack of texture, three-dimensionality, and sharpness, which causes the screen to become flowery, bald, mushy, and incomplete. Third, the tone imbalance. The gradations, sharpness, three-dimensionality, texture of the image, and the charm of the picture are achieved by the balance of the three main tones of light, midtone and dark tone. In the test, we found that there are some products that are too deep, too shallow, too flat, too blemish, light bald, dark paste and other quality problems. The picture with too dark tone is dark and old; the light picture lacks the sense of layering and three-dimensionality; the flat picture is dull and rigid; the overly-picture level is disjointed; the picture with bright tone and baldness is lost; the picture with dark tone is not Level feeling. The most prominent influence on the senses is bright tone and dark tone. The screen points of bare tone baldness are less than 5%, and even the net is absent; the overlay rate of shadow tone paste screen dots is as high as 290% (of course, there are less than 210%, obviously Too shallow. Therefore, the unbalanced tone of the textbook illustration screen has seriously affected the reproduction of the tone, three-dimensionality and texture of the picture. Fourth, the imbalance. The three-dimensionality and perspective of the picture are reproduced by the proper contrast of the image to the dark tone. Contrast of several images in one page is achieved by adjusting the contrast of certain images. However, the contrast of the illustrated textbook illustrations is indeed very irregular, and even very different, which seriously affects the quality of image reproduction. For example, when there is an image that is too large or too small in the page, it is always felt that the image in the page is in an unbalanced state, which seriously affects the negative integrity. The overall contrast is too small and the illustrations are pale, floating, gray, lacking in three-dimensionality and perspective. The effects of excessively large illustrations show baldness, embarrassment, and paste. In addition, some of the illustrations are flat, deep, and boring. The loss of a large number of tone levels will directly affect the overall quality of image reproduction. Fifth, the printing quality is very different. Due to the large amount of textbooks and the large number of companies engaged in printing, it is difficult to control the quality of products at a stable level. The differences in the management level, printing equipment, raw and auxiliary materials, and technical capabilities of the company and the quality awareness of the entire staff are important reasons for the unstable print quality of textbook illustrations. The examination of the printing quality of the textbooks also revealed that there were a considerable number of textbooks that were not overprinted, poorly formed outlets, light baldness, dark shadows, and other quality issues. The quality problems caused by overprinting are: blurred ambience, distorted colors, lost texture of the entire screen, and even affect the reader's eyesight. The quality problems caused by poor dot formation are: poor ink saturation, dull colors, dark shadows, poor clarity, and lack of texture. The quality problems caused by the bright tuning show are: the image picture is incomplete, the bright-tuning network is not complete or the network is out of screen, and the picture appears uneven and uneven. The quality problem caused by dark paste is: the middle part of the screen is transferred to the shadow part and loses a large number of layers, and the image screen loses the ink luster, three-dimensional feeling and texture. It is not difficult to understand from the above-mentioned problems related to the quality of textbook illustration and printing. The rigorous review of textbook illustrations and the management of the printing process are important factors that result in unstable product quality and even inferior quality. Therefore, it is necessary to effectively control from the following aspects in order to achieve stability and improve the quality of textbook illustrations. First, pay attention to the quality of the original. In image reproduction, originals (traditional originals) are the basis and basis of product quality. Therefore, editors must not only pay attention to the content of the manuscript when choosing the manuscript, but also should pay attention to the printability of the manuscript. Specifically, the following points should be noted: The specific requirements for manuscripts of photographic works are: high definition, basically saturated colors, real (compared with natural scenery), complete picture, moderate overall contrast (color picture contrast is 1.00 to 1.70; color reversal film is 1.30 to 3.50), with no other serious defects. 2. The specific requirements for paintings (Chinese paintings, oil paintings, watercolors, etc.) are: the picture is completely flat, no serious damage, no obsolescence (referring to modern works), and no piebald etc. 3. The specific requirements for the second manuscript (color reversal film or negative film reprinted color photographs reproduced with paintings and prints) are: Better clarity (accurate overprinting), basic colors, and complete picture Offset printing, accurate version, no reflective spots, etc. The common problem with secondary manuscripts is poor resolution, local "reflection points," and inaccurate printing. When encountering a manuscript with such defects, improvement suggestions and requirements should be proposed in advance so that they can be resolved in pre-press processing (art recreation). 4. The specific requirements for printed manuscripts (prints of different substrates) are: accurate overprinting, clear gradation, basic colors, and complete picture. In the original manuscripts (secondary manuscripts), there are often printed copies. When the selection is made, it should be based on the accuracy of the printed version and the basic consistency of the two parts. Unacceptable editions, distorted colors, prints on the layout, and severely folded, damaged prints cannot be used as copy originals. Second, the standard selection of mesh lines. The outlets are the basis for the reproduction of fine print images. Therefore, the standard selection of the mesh line is an important link in the printing of well-printed products. The author believes that printing companies can be divided into two categories according to their ability to print textbook illustrations (management level, equipment conditions, technical capabilities, etc.) and paper and other raw and auxiliary materials. One type of corporate equipment and technical conditions are superior, and can be used Slightly detailed mesh plate making (150 lines to 175 lines); second type of enterprise, compared with one type of enterprise, equipment, technology, etc. (to be continued)