Film output and quality design

First, design and production

As a design maker, they all hope that their own electronic files can be completely and smoothly output at the output center and get satisfactory films. However, when the output center is outputting, this or that problem often occurs. In fact, many problems are caused by improper design and production. These problems are not complicated, as long as the following aspects are taken into account in the design process.

1. Font

Usually, designers will choose various fonts to meet their own design needs. However, there are many kinds of fonts and the output center cannot have all the fonts. Therefore, when the design maker makes the fonts that the output center does not have, it will appear. Such as carefully selected fonts become other fonts, characters garbled or blank and other issues. Therefore, the design and production staff should first use the Chinese fonts that Hanyi, Wending, and Fangzheng use in the industry. Second, they should also understand the fonts of the output center so that their Chinese and English fonts are consistent with the existing fonts in the output center. Copy a font to the output center, or convert the text used in the file into a path as much as possible, so that it becomes a graphic, so that the text can be printed normally. However, the generated file contains a lot of curve information, which will cause some pressure on the output device.

In addition, PS files can also be generated and delivered directly to the output center. In this way, there is no need to consider the problem of mismatched fonts, but the premise is to have a certain understanding of the output center RIP and imagesetter. Since not all PS files generated by the layout software and all RIPs are compatible with each other, it is better to select the same printer driver and the same print description file (PPD) as the output center. It is worth noting that before generating the PS file, make sure that the typesetting file is correct, because the generated PS file cannot be changed at the output center.

2. image

Image loss, insufficient resolution, and bleeding errors often result in the inability to output film or the output of a film that is of poor quality and cannot be used for plate making. These issues are of great concern to the designer. Therefore, during the design and production, all the image files should be sent to the output center together, and the correct image path and sufficient resolution can be guaranteed. In addition, the image should be set to the CMYK printing color mode, because other modes are not applicable to print. Only in this way can a satisfactory film be obtained.

3. Output settings

Designers may not necessarily consider whether the page size of the electronic file matches the size of the output film. If the two are inconsistent, the film will be wasted. In order to save the cost, the output center must change the page settings of the original document. These changes are time-consuming and may also lead to other problems that should not have arisen. If the design and production staff can take this into consideration in advance, it will greatly benefit the improvement of the film output efficiency and the reduction of the document error rate.

In addition, when drawing a rule line, the line type must be “very fine”, and the four-color printing timeline should be defined as the CMYK color mode, and the four-color mode should be 100% solid color.

Second, RIP

RIP is the conversion of print data into rasterized images or dots for the output of film on a laser imagesetter or for printing on a printer. RIP receives print data in the form of descriptive languages ​​or vector images.

RIP has many output control parameters and must be determined and adjusted before output. Such as: select the file, picture path, exposure value, registration mark, simple and mixed row, missing chart error are all necessary parameters.

The pictures produced by Photoshop software have 8-bit 256-level images. After the photo-taking, all the elements of the picture can be represented. The following formulas must be met:

Control mesh number X 256-2<Phototypesetter output accuracy

During the output process, all parameters of the corpse should be adjusted before confirming that each value is correct before output.

Three, laser phototypesetting machine

When outputting the film, make sure that the laser imagesetter is in an absolutely normal and good working condition and perform regular calibration of the laser imagesetter. From the perspective of optimizing the operations of the imagesetter, periodic calibration of the equipment ensures that the equipment produces the correct film density. A small problem with the imagesetter can cause film waste and film drop efficiency. It can also lead to excessive film bottom ash, insufficient density, uneven layout, inaccurate on the ground, missing layers, missing meshes, stencils, etc. .

Phototypesetters mainly include winch type and drum type. The winch type photosetter has a relatively low accuracy. The drum phototypesetter is divided into two types: inner drum type and outer drum type. The outer drum type is faster but the precision is slightly lower. The inner drum type has high precision but slower speed. The experimentally measured high-definition inner cylinder drum phototypesetter output 4 films whose repositioning accuracy can reach ± ​​5μm.

The following methods can effectively improve the output efficiency of the imagesetter.

1. Sometimes changing the direction of the phototype page can greatly increase the imaging speed. For example, a page such as stationery, with the long edge in the axial direction during exposure imaging, saves both exposure time and material.

Fourth, film

1, film linearization

The separation film reflects the change in the level and color of the image as a percentage of dots. If the linearity of the film is not good, the printing effect of the image will be directly affected, which may result in text distortion, color cast of the shading of the picture, poor level reproduction, and the like. In order to eliminate the above problem, it can be solved by adjusting the film output linearity. The specific operation is as follows.

(1) Make a 0-100% 21 Gradient Scale in Photoshop.

(2) After determining the resolution of the imagesetter, output the scale.

(3) Comprehensively adjust the exposure intensity of the photosetter, the temperature and time of the film press, etc., and rinse the film on the scale.

(4) Measure and record the percentage of 0-100% of all levels of outlets.

(5) Compare the measured value with the standard value of the grading scale to determine the gradation transformation curve in RIP. If the standard is 50%, the measured value is 53%, indicating that the network point has been expanded by 3%, and 50% of the RIP needs to be changed to 47%.

(6) Repeat the above operation to control the error value of each network point within 2%.

(7) Flatten the curve and save the linear calibration parameters.

2. Comparison of Domestic Films and Imported Films

Compared with imported films, the highest density, fog, hardness, contrast and other properties of domestic films are relatively good. The main problem is that the linearity is not good.

After the use of domestic film, there will be a large error in the value of the output network. The direct consequence of this is that the picture is of the same grade, the color is inaccurate, the text is thick and thick, and the original reproduction is seriously affected. Therefore, the use of domestic film should first adjust its linear parameters.

3. Network control

When film output, the choice of network parameters (including dot shape, number of screen lines, screen angle) is also very important. In the printing process, circular dots are generally used, and the angle of the CMYK cable is set to 15°, 45°, 90°, and 75°, respectively. As for the determination of the number of screen lines, it is necessary to take into consideration factors such as manuscripts, paper, and ink. The larger the number of lines, the better the printing effect of the image, but it cannot be too large, otherwise it will result in the image hierarchy and even the phenomenon of stencil. The general newsprint printing uses 85-100 lines/inch, the offset paper uses 100-150 lines/inch, and the coated paper uses 150-200 lines/inch. The screening angle can use the default value while checking whether the grayscale conversion curve called is correct.

To reduce the occurrence of moiré or rose spots, one must increase the number of screen lines, and second, avoid the use of elliptical dots with high eccentricity to use symmetrical dots such as circles and squares. In theory, the FM network will not produce moire.

4. Repeatability of film positioning

The level of repeatability of the film directly affects the efficiency of platemaking, photocopying and printing quality. The alignment accuracy of the imagesetter for outputting color separation films cannot be ignored. Four-color film is required to repeat the positioning error <0.1mm, to ensure four-color film registration, no ghosting, multiple eyelids and other phenomena. Experiments show that by adopting some technological means, it can completely meet the requirements of repeated positioning accuracy (control the error within 10μm).

In order to meet the requirements of film repetitive positioning accuracy, the following points should be noted when outputting the film.

(1) After a roll of new film is finished, it should be used to output a color version of the film after at least five sheets of non-colored film have been output.

(2) A set of 4 films is output continuously as much as possible at once.

(3) Use a relatively loose collection box. The importation of the collection box, reels, etc. should be particularly relaxed so as not to block the film.

(4) According to the different conditions of the retracting box, 2-4 sets of four-color film can be continuously output, generally no more than 4 sets, it is recommended to continuously output 2 sets.

5. Film flushing

The quality of the film has a lot to do with its washing process. The first high-quality film is to have a sufficiently high density of dots: Second, the dots should be clear and not imaginary; third, the film should be bright and the fog should be less than 0.04.

In order to ensure the quality of film processing, attention should be paid to the following points: First, it is necessary to have a good grasp of the developer and fixer concentration; secondly, the time and temperature for developing and fixing should be set correctly; thirdly, the developer must be replaced promptly. Fixer; Fourth, the liquid should be evenly mixed, not because of the liquid did not stir well and the film density uneven.

The washed out film is mainly prone to problems such as white spots and scratches. The white spots are caused by insufficient fixing. Generally, the concentration of the fixing solution is not enough, and the amount of medicine is not enough. So long as the film is re-inserted from the fixing inlet of the washing machine, after washing and drying, the white spots on the film will disappear. . The appearance of scratches may be due to the deformation of the machine hardware in the direction of the processor. This requires that we periodically clean the film processor with a cleaning agent, and the roller must be scrubbed with a damp cloth to avoid the formation of crystals.

In the film flushing process, it is necessary to carefully check at any time and find that abnormalities are dealt with promptly. Because the film output is slow, in order to prevent the waste film from appearing, it is better to check the filming machine before flushing the film. If there is any problem, it should be adjusted in time.

As the final process, film inspection should really play a role in mending leakage and should pay enough attention to it. After the correct film is cut, it can be made into a print, then printed and printed.

In summary, as long as we reasonably grasp and make good use of design and production, RIP, laser photocopying and disposing machinery, and film during the printing process, we can obtain an ideal film output effect and improve the quality and efficiency of the output film. In this way, we can guarantee the high quality of printed products, so that enterprises can be invincible in the market competition.