Countermeasures against the unsatisfactory origina

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Countermeasures to deal with the unsatisfactory original print of newspapers

most operators only adjust the resolution, zoom ratio and other options when using the scanner to scan images, and the rest use the default settings. Practice has proved that this can not obtain the best scanning effect. Especially when the original image is defective, the scanning result is even worse. When scanning defective images, how can we give full play to the best performance of the scanner and scan high-quality images? This requires careful analysis of the original, making full use of some original correction functions provided by the scanner, and carefully adjusting the preset values of the scanner

I. the brightness and contrast should be adjusted during scanning for the pictures with inaccurate exposure. The pictures with excessive exposure look white due to their high brightness; Underexposed pictures look dark due to low brightness. At the same time, the images are lack of levels and details. At this time, we can drag the slider on the brightness and contrast slider to make the image have moderate brightness and contrast. Since the adjustment of brightness and contrast is effective for all pixels in the image, care should be taken not to lose sight of one or the other. For example, the main information of an image is located in a darker area. Making it brighter can make the details more obvious. However, if you use the brightness adjustment function to lighten all areas, you will lose all details in the areas with higher brightness

II. Color balance should be adjusted during scanning for color biased pictures. If the image is somewhat color biased, the overall color tone of the image can be changed by using the color balance option. If the color deviation is not serious, you can select the "automatic color balance" option to let the software automatically correct; Manual adjustment shall be carried out in case of serious color deviation. The color of the scanner is mainly a mixture of red, green and blue. The scanner provides adjustment functions for these three basic colors. There are three sliding bars in the adjustment options: red, green and blue. To adjust the image color, simply drag the slider on the slider bar to the color you want to add to the image, or drag the slider away from the color you want to reduce. To adjust the color, you need to master some knowledge of chromatics, especially the principle of complementary colors: the two colors in relative positions on the color wheel are called a pair of complementary colors, such as red and cyan, green and magenta, blue and yellow are complementary to each other. The so-called complementarity means that the reduction of a color in an image will inevitably lead to the increase of its complementary color. It is absolutely impossible for a color and its complementary color to increase or decrease at the same time

III. the gamma value shall be adjusted during scanning for pictures lacking levels. The gamma value affects the hue of the middle value of the graph or the gray level of the middle level. By adjusting the gamma value, we can change the brightness value of the gray scale of the middle tone of the image, so as to increase the middle level of the image, without much impact on the levels of the dark and bright parts. If you enter a number larger than one, the range of intermediate tones will be expanded. In this way, images with a large proportion of intermediate tones can produce less contrast and more details. Entering a number smaller than one will narrow the range of the middle tone, which will increase the contrast of the image and reduce the details of the image. When the curve moves downward, the corresponding pixels of the image become dark; As you move up, the corresponding pixel lights up. Its adjustment often needs to be used together with brightness and contrast to achieve satisfactory results

IV. pictures with poor composition

should be cut reasonably during scanning. Pictures with improper framing often have disordered backgrounds, unobtrusive themes or skewed scenery, resulting in poor visual effects. When scanning, you can select the scanning range to choose or reject the original image, correct the skewed image and re create the art. The specific operation is to select the "scanning size" as the "user defined" mode in the scanning setting option, and then select the area to be scanned by dragging the selection box in the preview image window. The method is as follows: hold down the left mouse button at one corner of the area to be scanned, drag the selection box to the opposite corner of the scanning area, and release the left button. In this way, the scanner will automatically scan only the selected area. For pictures with skewed scenery, just use the "rotation" function to correct them

v. the image to be printed

shall be scanned with the function of removing lines. In the printing field, the hanging printing technology is used, which relies on countless dots of different sizes to show the brightness of the image. These dots are acceptable to the naked eye, but it is a problem that cannot be ignored for the scanner, because the scanner will scan these dots when scanning the printed photos, which will affect the image quality. The removal technique can analyze the image with dots, restore it to the original without dots, and reproduce the effect of the original image 9 GH m 0250 m D60 1a01 represents the series in which GH accounts for 87.38% of China's total non-ferrous metal imports in the same period, with m18x1.5 thread, 250mm stroke metric, D60 plug and 4 ⑵ 0ma output. Scanners generally have several options for us to choose from. When the original image is a magazine or film covered printed matter, please select "magazine"; When the original picture is a newspaper or a rough dot print, please select "newspaper"; When the original image is a high-quality fine print, and the point is very small, please select "art print". It should be noted that if non printed matter is scanned, select "not set" and do not turn this function on, because it will reduce the quality of the scanned image

by modifying the scanning parameters, some shortcomings of the original image can be made up and the scanning effect can be properly improved, but the effect is always limited. To get the ideal scanning effect, the best way is to choose a good picture

VI. pictures downloaded from the Internet

most pictures downloaded from the Internet are in RGB mode, and the color range of RGB mode is larger than that of CMYK mode. In order to ensure the printing effect of images, it is best to use RGB mode for processing, and finally convert to CMYK mode. Select the CMYK preview option in the View menu when you view an image in RGB mode in Photoshop. That is, the image is displayed in RGB mode and CMYK mode. Because most of the downloaded images are of display size, the area is small. When we want to make the images needed by the newspaper, the images will become not clear enough. If there are mosaics, we should pay more attention to the fact that we should not sharpen too much when sharpening. We should properly blur them first and then sharpen them. If the original image is a color image, but it is to be used in a grayscale layout, do not directly convert the original image to grayscale mode during processing. RGB mode shall be used for processing. The processed image shall be first converted to the image in L * a * b * mode, and then through the channel separation command, the image in L * channel shall be selected as the gray-scale image for printing in the field of chemical anti-corrosion. It should be noted that the RGB and CMYK modes should not be converted to each other, and the two modes should not be switched back and forth, because in the lattice image software, every time the image color space is converted, some details of the original image of an innovative biosphere of graphene must be created, which wangzhonghui believes is the first step

precautions in the processing of paper printed images: in order to make the color bright, the main color should be appropriately emphasized, and the opposite color should be appropriately reduced or not used; The dark tone and bright tone shall be properly omitted; The face value of the black-and-white image of the character should not be too high to avoid being too black. The brightness should be enough

in a word, I have deep knowledge and experience in the scanning and production of images in the prepress system. Therefore, the operator of the prepress system must be able to master various skills of image processing, improve his aesthetic outlook, accurately judge the quality of the picture, and really get a good picture printing effect. Don't be afraid of trouble, carefully adjust, and strive to achieve the effect that the processed picture is of higher quality than the original

Author: Zhaoli source: Shandong newspaper

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