Discussion on the pre-press graphic processing and grouping skills of the color report
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At present, most county and municipal newspapers are mainly based on four editions and four editions. The circulation is about 20,000 copies, and sometimes it is necessary to print a small number of color newspapers at the big newspapers. However, the same printing machine is processed by the same software. The printing quality of the small color newspaper is good, and it is far from the hundreds of thousands of printed newspapers. The reason is mainly because the normal running speed of the paper tape of the high-speed rotary machine is 9-13 m/s, and the printing number of the small color newspaper is usually only about 10,000 copies, and the color is not adjusted to the best state and printed.
To solve this problem, on the one hand, it is necessary to require the staff of the machine to be accurate and fast; on the other hand, in the pre-press processing of the small color newspaper, the typesetting staff should try to cooperate to make the color adjustment during printing relatively It is easier to speed up the color adjustment speed of small color newspaper printing.
The pre-press processing of the color report includes image processing, group printing, output, plate making and other processes. The following is to improve the printing quality of small color newspapers through image processing and adjustment of the group version.
Image color and level adjustment
The image plays an important role in the color report. In the color printing, the image quality is good, and the coloring time can be reduced during printing.
1. Processing color images in RGB mode
The RGB mode is a color scheme used in optical-based devices that can express more colors, especially bright and bright colors.
Image editing processing often goes through many steps. If you want to combine the contents of several images, you need to adjust them because the original colors of the components cannot be the same. Regardless of the effect of image processing, the operator wants to make the picture as real and rich as possible. Since the color range of the RGB mode is much larger than the CMYK mode, when the image is processed in the RGB mode, a wider color space and more editing effects are obtained. Although it must eventually be converted to CMYK, and there will be color loss, it is much better than losing the image color from the beginning.
2. Image sharpness adjustment
Compared with high-grade printing, due to limited printing materials and conditions, the number of image network lines is low, and the printing dot gain rate is high. Therefore, in the adjustment of small color newspaper images, large sharpening values are needed to improve image clarity. .
From the screening process, sharpening has the effect of eliminating the loss of gradation due to screening. Therefore, sharpening is a necessary step in prepress processing. The degree of sharpening is related to the type of original image and the zoom magnification. Usually, the sharpness of the image of the character is smaller, and the landscape draft can be larger; the larger the image, the greater the sharpness; the higher the magnification, the sharpening degree The deeper it is.
3. Image level adjustment
The purpose of the level adjustment is first to meet the printing requirements, and to compensate for the increase of the dot according to the characteristics of the high rate of increase in the printing dot of the newspaper, and to concentrate the main layer in the middle zone, that is, 20% to 60% of the visually sensitive zone. The tone of the original is maximized to correspond to the tone that can be reproduced by the print to make the image clear and true. Secondly, according to the content of the manuscript and the hierarchical distribution, the tone of the important parts is guaranteed to be accurate. For example, the clothes and faces of the characters must be clearly leveled, 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 net, the image network point tone is generally controlled between 2% ~ 95%.
4. Image color adjustment
The adjustment of the image color, also known as the school color, is mainly reflected in the reproduction of the original, not the color of the original. In the adjustment process, it is mainly to correct the color shift caused by the original or scanning, to ensure the accuracy of the color of the main part; and to ensure that the screen effect and the final printing effect are compatible.
Note that newsprint has a grading of 3% to 5%. It is best to open the original digital file against the proofs or the standard printed matter, and compare the color correction. At the same time, the school color adjustment should be based on the information displayed on the information board, and it cannot be displayed on the screen alone.
5. Convert RGB mode to CMYK mode
The image used for printing the film must be in CMYK mode, so the image mode should be converted before the film is released. The image in CMYK mode has no bright image in RGB mode. After conversion, check the image first, and then confirm the output without color cast. If you are not satisfied, you should immediately cancel the color mode conversion, and then switch it back to RGB color mode, otherwise it will cause color loss.
Group adjustment
The grouping process is also an important aspect of the quality of the color report. The use of the layout color will affect the positioning, theme and style of the entire layout. Therefore, the typesetting staff must use the color reasonably and make appropriate adjustments, thereby reducing the time for adjusting the color during printing and improving the printing quality of the small color newspaper.
1. Image size adjustment
The impact of image quality cannot be ignored during the grouping process. First, don't zoom in or out on the image in the group software when you are in the group. Shrinking the image will make the effect worse and the output slower; while the magnified image will have a greater effect on the image, if it has to be changed, it should be done in the image processing software.
Secondly, pay attention to the image pressing problem, the pressure word can not be too much; do not use the negative word, otherwise it will affect the image effect.
Third, the words and images should be kept at a certain distance. Do not over-squeeze or loosen them, so as not to affect the overall effect of the graphics.
2. The processing technique of shading in the layout
The correct use of shading to make it part of the layout language is an important part of printing a small color newspaper.
(1) Shading color selection should be reasonable
If you must use a yellow shading, it is best to use 100% pure yellow, because yellow is easy to see on white newsprint, it is difficult to have high print quality; if there are black characters in the shading, and black characters are not hooked, Use purple, cyan, green, red and other shading instead, because they are less visible with black characters and should be avoided.
(2) The use of sub-solid color, solid color, and less complex color
Because the complex color is multi-color overprinting, it will inevitably increase the difficulty of color chasing in small color newspaper printing, making the color difficult to print and prone to color cast phenomenon.
(3) Avoid printing color blocks on text
Especially when it is a small number, it is easier to reduce the visibility of the text. The background color of the text should be based on the premise of not obstructing reading. Therefore, for a small text with a certain length, it should be a soft and light tone background, avoiding the use of dark blue, blue and purple dark shades.
3. How to deal with layout text
In general, the body of the color newspaper is black, because black is the most visible on white newsprint, and it has the least amount of stimuli to the reader's visual color, which can reduce reading fatigue. If the content of the text must use colored words, it is generally suitable to use purple, cyan and other colors that are more visible on newsprint, and less use of gray, red and other colors with low visibility, basically can not use yellow.
The title of the article is usually larger, and the number of words is small. You can use high-definition, high-purity colors such as yellow, red, and orange to attract the reader's attention and make the layout jump. At the same time, it is easy to print from the printing point of view. Out of effect. Of course, for the overall needs of the layout, soft pastel shades can also be used.