Graphic newspaper design graphic processing and making skills

Caipai prepress processing includes image processing, group printing, output, and plate making. The following adjustments are made through image processing and group printing to improve the quality of small color printing.

Image color and level adjustment

The image plays a very important role in the color newspaper. In the printing of the newspaper, the image quality is good, and the coloring time can be reduced when printing.

1. Processing color images in RGB mode

RGB mode is the color mode adopted by the device based on the optical principle, it can express more colors, especially bright and bright colors.

The editing process of the image often goes through many steps. For example, if the contents of several images are combined together, since the original tones of the various components cannot be the same, they need to be adjusted. Regardless of the effect of image processing, the operator wants to make the picture as realistic and informative 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 varied editing effects will be obtained. Although it must eventually be converted to CMYK, and there will certainly be a loss of color, it is always better to lose the color of the image than it was initially.

2. Image sharpness adjustment

Compared with high-end printing, due to the limited printing materials and conditions, the color newspaper has a lower image line number and a higher printing dot rate. Therefore, in the adjustment of small color picture images, it is necessary to use larger sharpening values ​​to improve image sharpness. .

From the screening process, sharpening has the effect of eliminating the loss of gradation that occurs due to screening. Therefore, sharpening is a necessary step in prepress processing. The degree of sharpening is related to the type and scaling factor of the original image. Usually, the sharpness of the human image is smaller, while the landscape draft may 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 grading adjustment is to meet the printing requirements first. According to the characteristics of high rate of increase in printing outlets of newspapers, compensation for the increase of outlets will be concentrated in the middle area, that is, 20% to 60% of visually sensitive areas. The gradation of the original corresponds to the gradation that can be reproduced by the printing to make the image clear and real. Second, according to the manuscript content and level distribution, to ensure the accuracy of important parts of the tone, such as the character's clothes, face, etc. must be clear, the level of the difference should not be less than 15%. In addition, adjust the value of extremely high light or dark tone, not a large area of ​​network, the image tone adjustment is generally controlled between 2% to 95%.

4. Image color adjustment

The adjustment of image colors, also known as color correction, is mainly reflected in the reproduction of the original, rather than the color of the original itself. In the adjustment process, the color shift caused by the original or scanning is mainly corrected to ensure the accuracy of the color of the main part, and the screen effect and the final printing effect are also adapted. Note that newsprint has a grayscale of 3% to 5%, and it is better to compare the standard digital prints with the proofs, open the original digital files, and compare the colors. At the same time, school color adjustments should be based on the information displayed on the information board, and cannot rely on the screen display effect alone.

5. Convert RGB mode to CMYK mode

The image used to print the sheet must be in the CMYK mode, so the image mode must be converted before the film is released. The image in CMYK mode is not bright in the RGB mode. After the conversion, the image should be checked first, and then the image should be output after determining the color shift. If you are not satisfied, you should immediately cancel the color mode conversion, and should not be converted back to RGB color mode, otherwise it will cause color loss.

Group adjustment

The process of group edition is also an important aspect affecting the quality of color newspapers. The use of layout colors will affect the orientation, theme and style of the entire layout. Therefore, the typesetting personnel must use color reasonably and make appropriate adjustments, thereby reducing the time for adjusting color during printing and improving the printing quality of small color newspapers.

1. Image size adjustment

In the process of group edition, the influence of image quality cannot be ignored. First of all, do not arbitrarily enlarge or reduce the image in the build software when you make a layout. Decreasing the image will make the effect worse, and the output will be slower; while the enlarged image will have more influence on the image effect, if you must change the size, you should do it in the image processing software.

Secondly, pay attention to the problem of embossing the image. The embossing cannot be too much; do not use a vignette, otherwise it will affect the image effect.

Third, texts and images must be kept at a certain distance. Do not over-crowd or loose them so as not to affect the overall effect of the text.

2. Shading in the layout of the processing skills

The correct use of shading to make it part of the layout language is an important part of printing small newspapers.

(1) Shading color selection should be reasonable

If it is necessary to use 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 printing quality; if the shading is black, and the black word is not edged, It is necessary to use less shades of purple, cyan, green, and red because they are less visible with black characters and should be avoided.

(2) shading more solid color, solid color, less complex color

Because the polychromatic color is overprinted, it will inevitably increase the difficulty of color-tracking in the small-colored newspaper printing, making it difficult to print the colors and causing color casts.

(3) Avoid printing color blocks on text

Especially in the case of trumpet characters, it is easier to reduce the visibility of the text. The background color of the text should be based on the premise that it does not hinder reading. Therefore, for a small number of characters with a certain length, a soft and light tone background should be appropriate, and dark shades such as blue-green, blue-violet, etc. should be avoided.

3. How to deal with layout text

Under normal circumstances, the body text of the color newspaper is black, because black is most visible on white newsprint, and it has minimal visual color stimulus to readers, which can reduce reading fatigue. If the content of the body text must be colored, it is generally appropriate to use purple, cyan, etc., to make the colors more visible on newsprint, and to use less visible colors such as gray and red. Basically, it cannot use yellow.