How to deal with more suitable for color printing

The printing quality of newspapers is the cornerstone of the survival and development of printing plants, the embodiment of the important competitiveness of newspaper printing tasks, and a key factor for newspapers to attract readers and increase market share. Continuously improving the quality of newspaper printing is an eternal theme in the development of newspaper printing. In the past ten years, with the large number of printing presses introduced and the continuous improvement of the level of technology, printing plants have been paying more and more attention to the management of printing quality, and the printing quality has been improved rapidly. In terms of overlay accuracy, tone reproduction, color quality, etc., To meet the needs of newspaper market competition, Caipao has become the mainstream of the newspaper market.

Under the relatively stable conditions of current printing equipment, printing materials and printing technology, the quality of the text ink and the quality of the field has been almost the same, and the quality of newspaper printing is increasingly reflected in the quality of color pictures. To evaluate a good picture, it should be structured, moderate contrast, strong three-dimensional, and good color reproduction. However, when we deal with pictures, we have formed a relatively fixed pattern, that is, we simply adjust the curve to increase the contrast, instead of adjusting the level distribution of the image in a targeted way, especially affecting the highlights and shadows. The balance of gray was not dealt with enough, local emphasis was not enough, and adjustment was too conservative. We did not proceed from the reality of the print production of newspapers and more frequently copied the experience of coated paper printing. The pictures processed in this way generally have problems such as too many intermediate levels, ungradable tone levels, weak stereoscopic effect, dark colors, and poor visual effects. And some of them are too large in the middle tone, and the contrast is too large. The effect of merging tone with dark tone is also not good. Such a picture is not suitable for newspaper printing. The emergence of the problem is not the poor level of technology of the photo production staff. In the final analysis, it is not enough to understand the characteristics of newspaper printing. It is not right to know how the picture is handled and is more suitable for newspaper printing.

The printing of newspapers differs greatly from that of coated paper in the idea and method of image processing. Only with an in-depth understanding of the characteristics of newspaper printing, can it be clear how the image is handled and is more suitable for printing by color printing. This is also the current prepress production staff. What is missing. The greyscale of newsprint is much larger than that of coated paper (it is measured that the density of newsprint we are currently using is about 0.15 more than that of coated paper), and there is widespread color cast, which is equivalent to reducing the print contrast of pictures. The bottom ash of the color inks used in newspaper printing is relatively large, and the degree of saturation is not as good as that of copperplate printing inks. It also makes the color of the printed pictures darker, and the contrast displayed is relatively small, so the range of performance levels is also small. Therefore, when dealing with pictures, we must take into account the gray content of each tone of the picture to do a corresponding removal, and according to the characteristics of color cast to balance the removal of each color, effectively solve the problem of over-dark color printing pictures. The paper characteristics of newsprint paper and the characteristics of printing equipment determine that the tone copy range of newspaper printing is lower than that of coated paper (the latest national standard requires that newspapers have a tone reproduction range of 5% - 95%), so don't blindly deal with pictures. To preserve the level of the manuscript, it is necessary to appropriately increase the contrast of the picture according to the specific circumstances of the picture, and retain or compress some of the layers in a targeted manner so as to display the main body of the picture as much as possible. The brightness of the printed picture is good and the contrast is moderate. Colors are close to nature.

When dealing with pictures of landscapes, there should not be too little green. When appropriate, you can increase the proportion of blue and make the picture full of vitality. If you reduce the proportion of youth at this time, the picture will look old and no beauty. In the processing of pictures, the adjustment of blue and black plays a significant role, but this does not mean that red and yellow can be ignored. Only according to the different requirements of different pictures, the proportion of CMYK can be handled correctly to make a good picture.

When we were dealing with an overexposed or underexposed image, there was no good way before, but now we have some experience with this kind of picture. Overexposed images themselves appear to be white due to high brightness; underexposed images look dark due to low brightness. Both images lack levels and are not rich in detail. At this time, we can drag the sliders on the brightness and contrast sliders to make the image brightness moderate and the contrast suitable. Since brightness and contrast adjustments work on all pixels in the image, care should be taken in adjusting them. For example, the main information in the picture is in a dark area. We can circle the darker area and make it brighter to make the details more visible. In addition, we can boldly add saturation, so that the picture as a whole has a sense of hierarchy, which is also not commonly used before.

If there is a color cast in the image, you can use the color balance option to change the overall hue of the image. Now we generally use color balance for color adjustment in the RGB format, and the use of color balance requires us to have some knowledge of color science, especially the principle of complementary color (two colors in the relative position on the color wheel are called a pair Complementary colors such as red and cyan, green and magenta, and blue and yellow are complementary colors. The so-called complementation is the reduction of a color in an image, which inevitably leads to an increase in its complementary color. It is absolutely impossible for a color and its complementary color to increase or decrease at the same time. Through the use of complementary colors, we can effectively correct the color cast. We can also properly adjust the color of the image to make the color of the picture brighter. This technique is more difficult to grasp, and we need to slowly explore and accumulate it at work. experience.

When dealing with unsatisfactory composition images, if the composition is not ideal, they will make reasonable cuts for themselves in the typesetting. Pictures with inappropriate viewing angles often have chaotic backgrounds, inconspicuous themes, or skewed scenery and poor visual effects. We can select the original image after editing with the editor as needed, correct the skewed image, and recreate the art.

Most of the daily pictures we use in newspapers are digital cameras directly taking pictures, Xinhua News Agency providing pictures and downloading pictures on the Internet. Scanners scan fewer and fewer pictures. This reduces the number of scanners we use. Loss of color and effects when processing photos. On the other hand, when the downloaded image is too low, the enlarged image becomes unclear. If there is a mosaic, it is even more important to note that it is not possible to sharpen too much, and blurring should be done first.

The mode of processing pictures should be based on the RGB mode, because the color range of the RGB mode is larger than the CMYK mode. To ensure the printing effect of the image, it is better to use the RGB mode for processing, and finally convert to the CMYK mode. It is important to note that do not convert multiple times between RGB and CMYK modes, as this will lose some of the detail of the original image. This is very important.

During this time, in order to grasp the essentials of image processing, the comrades in charge of the production of pictures are particularly attentive. On the one hand, they have increased the intensity of adjustment for the characteristics of newspaper printing and dared to make bold attempts. On the other hand, they referred to domestic well-made newspapers to learn advanced experience. Whenever they have time, they sit in front of a computer to adjust their pictures. Sometimes a picture has to be adjusted several times before being satisfied. Even after finishing the layout, it feels that there are places that are not satisfied enough, and then the pictures are transferred and adjusted. Say that in order to improve the quality of the pictures, they have devoted much time and energy. It is gratifying that their efforts have paid off. Recently, the quality of the production of our daily pictures has been significantly improved. Mainly in the picture is no longer stuffy and dark, but a lot of bright, moderate contrast, the level of more clear, with the previous picture dark hair stuffy and not bright enough, a strong contrast to form a sharp contrast. Even if some of the original images are not good during the processing, after careful processing, the final report results are also good. The apparent improvement of the quality of these pictures shows that only from the actual characteristics of newspaper printing production will the produced pictures be more suitable for newspaper printing.

At the same time, we must also clearly understand that the scanning and production of the prepress system images must grasp various techniques of image processing, enhance their aesthetics, and accurately determine the quality of the images. Really get a good picture printing effect Do not be afraid of trouble, repeatedly and carefully adjusted, and a picture may need to be adjusted several times, the adjustment time may be longer at the beginning, at the same time will be subject to tight working hours, typesetting tasks and other issues . However, after a period of accumulated experience, when we can correctly grasp the methods, the time will be shortened accordingly, and the images will become easier to handle, and the quality will also be greatly improved.

Source: Shandong Newspaper Industry