Discussion on the Influence of the Technical Level of Photo-distribution Center on the Quality of Color Newspaper (Part Two)

2. Image adjustment

In the picture processing process, the following points must be mastered:

1 Picture level adjustment. One is to compensate for the expansion of outlets during the printing process, focusing the main level on the visually sensitive area of ​​10% to 60%, that is, to make the gradation of the original document correspond to the gradation that the printing can reproduce to the maximum extent, so that the image Clear and true; on the other hand, according to the content of the manuscript and the level of distribution, adjust the visual response of the high, medium and low-key levels.

2 school color. The color correction is to reproduce the color reflected by the original (not the original itself). In the operation process, it is mainly to correct the color shift caused by the original or scanning, to ensure the accuracy of the main part of the color, to ensure the accuracy of the basic color, and to adapt to the actual effect of the unit's printing press. When coloring, you should value the specific parameters of the picture instead of relying on the screen only.

3RGB to CMYK format conversion. The format of the picture used for printing the film must be CMYK format, and the color separation parameter setting will directly affect the printing effect. In the color separation parameters, the black generation range, the maximum amount of ink, the color separation mode, and the dot enlargement are all very important. It needs to be changed according to the printing conditions and should be in good agreement with the printing conditions.

4 sharpening. Sharpening is an effective way to improve image clarity. Sharpening also has knowledge. Too small a level is plain and too big will make the level too awkward. Compared with the high-end printing, because of the limited printing conditions, the dot-printing rate is high, the coarse mesh, and the large tax value are conducive to improving the image sharpness. Generally, the screen effect can be adjusted slightly. One thing to note is that the content is different, and the requirements for sharpening are also different. For example, the landscape may be slightly smaller and the utensils may be slightly larger. From the perspective of the hanging net process, sharpening also eliminates the effect of the level loss that occurs due to the hung net. At this point, sharpening is by no means a process that can be done, but is a necessary process for processing images.

Third, the standardization and dataization of group edition and output process is an effective means to ensure and improve the quality of color newspapers

1. Edition

The group edition is the process of carrying out photo-text mixing. The standardization and standardization of the group edition is an effective means to ensure and improve the quality of the colour newspapers. The group edition should strictly follow the requirements of standardization and standardization. If the picture must be in CMYK format, change the size of the picture as much as possible in Photoshop, do not pull pressure, deformation pictures, text block, color block spacing should be standardized; text kerning generally do not change, loss of text can be passed through the punctuation Half-body adjustments make the layout beautiful.

2. Output

The output process includes several processes such as RIP dispensing, photosetter exposing films and rinsing, and inspection. Controlling this process with data and standardization is an important means of guaranteeing the quality of color newspapers.

Therefore, the following points should be noted during the output of the film:

1 Data control is the basis for a good film output process control and quality assurance. There are two aspects of the data control of the output of the film, one is to ensure the accuracy of the output network, the error of the color newspaper network should be controlled within 2%, and the second, the maximum density of the bottom ash of the film (D0) should be less than 0.04. The maximum density Dmax is between 3.5-4.0.

2 Careful operation, careful adjustment, and standardized operation are important steps to ensure output quality. The output must ensure that all layout parameters are consistent, and the number of hanging meshes meets the printing requirements (between 87Lpi and 133Lpi, black and white, red version at 87Lpi or 100Lpi, color version at lOOLpi or 133Lpi), and the net angle is accurate and does not produce moire. The four-color version repeat positioning accuracy is within 0.02mm, and the position, size, and thickness of the registration mark are uniform.

IV. Coordinating the relationship between photocopying and plate making and printing processes is an important condition for improving the quality of colour newspapers

The photocopying process is very different from that of the plate making and printing process in terms of technical nature. The phototaking process is a process from an analog manuscript to a digital document and then converted into a simulated film. It is the basis of other processes, but it also needs to meet the requirements of plate making and printing processes. The various processes can work together to produce good news.

1. Standardization and dataization are the basic principles that should be followed in photodistribution, plate making, and printing.

Every procedure must be tested in accordance with the requirements of normalization and data manipulation, and the process must be controlled. As the photocopying process, a set of standardized data files suitable for photocopying quality should be established according to the process conditions and levels of the unit's plate making and printing, and corresponding instruments such as spectrometers and densitometers should be equipped.

2. Proofing is an effective means to test the quality of photocopying work and to distinguish the control responsibility of photocopying, plate making and printing.

The purpose of proofing is to standardize the operation of the subsequent process to verify the quality of photocopying work, and at the same time provide a template for printing. Proofing paper and ink are used as much as possible for actual printing materials. Due to the news and timeliness of the newspapers, the conditions for proofing may not be allowed each time, but some lived and played several times will benefit the photocopying process to further adjust their own process parameters, which is conducive to the gap between platemaking and printing to find their own work.

3. Cooperation and common improvement are favorable conditions for doing good coloring

The photocopying staff should learn more about plate making and printing, and learn more about some process requirements of the control line in the next process. At the same time, the plate-making and printing process must also reflect their own process problems to phototypes in a timely manner. I believe that the further improvement of the quality of color newspapers should be preceded by the adjustment of plate making and printing procedures in order to further discover and adjust the phototypesetting process parameters. Making color newspapers, the masters of color separation and mastery of color matching are the key to the production of photocopying.

In addition, as the price of CTP equipment and special plates for CTP declines, CTP technology becomes more and more popular. The technical level of photocopying will improve the quality of color newspapers, and the publication and printing time of newspapers will also be greatly advanced.