Image color and level adjustment
Image plays a very important role in color newspaper printing, in color newspaper printing, the image quality is good, in order to reduce the color mixing time.
1. Color images are processed in RGB mode
RGB mode is based on the optical principle of the device used in the color mode, it can represent more colors, especially bright and bright colors.
Image editing processing often has to go through many steps, such as to combine the contents of several images together, because the original tone of each component can not be the same, they need to be adjusted. No matter what the effect of image processing is, the operator wants to make the picture as realistic and rich in detail as possible. Because the color range of RGB mode is much larger than that of CMYK mode, when processing images in RGB mode, you will get a wider color space and more varied editing effects. Although you will eventually have to convert to CMYK, and there will certainly be color loss, it is much better than losing image color in the first place.
2. Image sharpness adjustment
Compared with high-grade printing, color newspaper due to the limited printing materials and conditions, the number of image network cables is low, the printing dot increase rate is high, so in the small color newspaper image adjustment, it is necessary to use a larger sharpening value to improve the image clarity.
From the point of view of the screening process, sharpening has the effect of eliminating the layer loss caused by screening, so sharpening is a necessary step in prepress treatment. The sharpening degree is related to the type and zoom ratio of the original image. Generally, the sharpening degree of the figure image is less, while that of the landscape image is larger. The larger the image, the greater the sharpening degree; The higher the magnification, the deeper the sharpening.
3. Image level adjustment
The purpose of level adjustment is first to meet the printing requirements, according to the characteristics of the newspaper printing dot increase rate, to compensate for the increase of the dot, the main level is concentrated in the middle area, that is, 20% to 60% of the visual sensitive area, so that the tone of the original manuscript to the maximum extent and the printing can reproduce the tone corresponding to the order, so that the image is clear and real. Secondly, according to the content of the original manuscript and the distribution of levels, to ensure the accuracy of important parts of the level, such as the character's clothes, face, etc., must be clear, and the facial level difference should not be less than 15%. In addition, adjust the value of extremely high light or extremely dark tone, not a large area of the network, the image dot tone is generally controlled between 2% and 95%.
4. Image color adjustment
Image color adjustment, also known as color correction, is mainly to reproduce the original manuscript reflected, rather than the original manuscript itself. In the adjustment process, it is mainly to correct the color deviation caused by the original manuscript or scan to ensure the accuracy of the color of the main part; Also make sure that the screen effect and the final print effect are appropriate. Note that newsprint has 3% to 5% gray scale, it is best to check the proofing sample or compare the standard print, open the original digital file, and compare the color. At the same time, the color adjustment should be based on the information board display data, can not only rely on the screen display effect.
5. Convert RGB mode to CMYK mode
The image used to print the film must be in CMYK mode, so the image mode must be converted before the film is printed. The image in CMYK mode is not as bright as the image in RGB mode. After conversion, the image should be checked first to determine no color bias before output. If you are not satisfied, you should immediately cancel the color mode conversion, do not convert it back to RGB color mode, otherwise it will cause color loss.
Block adjustment
The process of grouping is also an important aspect of affecting the quality of color newspaper, and the use of layout color will affect the positioning, theme and style of the entire layout. Therefore, typographers must make reasonable use of color and make appropriate adjustments, so as to reduce the time of color adjustment during printing and improve the printing quality of small color newspapers.
1. Image sizing
The influence of image quality can not be ignored in the process of compilation. First of all, in the group version, do not enlarge or shrink the image at will in the group version software. Shrinking the image will make the effect worse and the output slow; Enlarging the image has a greater impact on the image effect, and if the size must be changed, it should be carried out in the image processing software.
Secondly, we should pay attention to the problem of image pressure, pressure word can not be too much; Do not use negative characters, otherwise it will affect the image effect.
Third, the text, the image should maintain a certain distance, not too crowded or too loose, so as not to affect the overall effect of the text.
2. Shading in the layout of handling skills
The correct use of shading, so that it becomes a part of the layout language, is an important part of printing small color newspaper.
(1) The shading color selection should be reasonable
If you must use yellow background, it is best to use 100% pure yellow, because yellow is easy to see on white newsprint, it is difficult to have high printing quality; If there are black characters in the shading, and the black characters do not have a hook, it is necessary to use less shading such as purple, cyan, green, and red, because they are easy to see with black characters, and should avoid combination use.
(2) Background color multi-use secondary pure color, pure color, less use of compound color
Because the compound color is multi-color overprinting, it will inevitably increase the difficulty of color tracing in small color newspaper printing, so that the color is difficult to print accurately, and the color bias phenomenon is easy to occur.
(3) Avoid adding color blocks to the text
Especially in small letters, it is easier to reduce the legibility of the text. The background color of the text should be based on the premise that it does not hinder reading, so for small text with a certain length, a soft and light tone background should be appropriate, and dark shading such as blue-green and blue-violet should be avoided.
3. The processing method of the layout text
Under normal circumstances, the text of the color newspaper is black, because black is the most easy to see on white newsprint, and the visual color stimulation of the reader is the least, which can reduce reading fatigue. If the text content must use color words, it is generally suitable to use purple, cyan and other colors that are easy to see on newsprint, and use less colors that are easy to see, such as gray and red, and basically cannot use yellow.
