Laser image output film is an important part of the prepress output process. To output a high quality plate negative film, in addition to setting the output parameters correctly, it must also take corresponding technical measures according to the characteristics of the photo film, so it is necessary to know and understand the process of photo film. Technical requirements are very necessary.
According to the different characteristics of the light source of the imagesetter, the laser photofinishing film is generally divided into two types, namely HN and red laser LD. The direction of the film side is divided into inward or outward, and one phototype machine can only use the inner or outer roll. One of the films. The film used in the conventional phototypesetting machine has two types of axis size, the small axis is 2.0 inches (51mm long) and the large axis is 2.8 inches (71.9mm long). Soft and hard flange refers to whether there are black hard plastic plugs at both ends of the film. Generally on the same photosetter, the hard and soft flanged films can be used interchangeably.
Each imagesetter can only use film whose width is smaller than its maximum size. The length of the film that the imagesetter can install is determined by the size of its cassette.
Photographic film in use should pay attention to the following questions:
1. Although the ordinary photocopying film is a bright room film, the loading process can be completed under the indoor light source, but in the actual production, the operating rules should be strictly observed, and the film is loaded into the loading box as required, and the cover is mounted on the stage. , Tighten the screws on both sides of the top of the box (note that both sides are balanced with equal force) and then tear off the film lead so that the film exposed at the film exit is parallel on both sides, the width of 1.5-2cm, in the process of handling to support The bottom of the box prevents exposure of the film due to shedding.
2. Before each batch of laser illuminating film is put into use, basic density testing and linearization of the dot network should be performed. Then, corresponding technological measures are taken according to the test result, such as adjusting the laser focal length, exposure amount, and the temperature and time of the developing and fixing. In order to achieve standardized and scientific production, prevent the formation of non-lattice products.
(1) Film density is divided into high density and low density. Low density refers to the density at which the film is completely unexposed after rinsing, typically around 0.05. The lower the low density, the more transparent the film is and the better the quality of the printing screen. High density refers to the density of the film after it has been washed at 100% exposure. The printing film used in traditional coated paper requires a high density value of not less than 3.5, usually 3.5-4.5, which ensures that the image information on the film is well transferred to the printing plate during printing. When printing on newsprint and offset paper (including map paper), the high density of the paper may be appropriately reduced due to the strong ink absorption and high printing speed.
(2) Linearization refers to the process of color separation. It is required to ensure that the dot values ​​set in the computer can be truly reflected on the printed film. Take 50% neutral ash as an example, where 50% of screen points are required on the computer, the output must be 50% on the printed film, and the dot error should not exceed 1% of the soil. Otherwise, the distortion of the printed image will be caused. This is especially evident in color four-color printing. However, film development, the stability of the fixing conditions is difficult to guarantee, so the more rigorous approach is to test the linearization every day.
3, the desk adjusts the concentration temperature of the fixer and the fixing time.
(1) Other conditions remain the same. The higher the developer concentration, the higher the temperature, the higher the density of the film. If the film is washed with a domestic developer (eg Aibisi SH-1000), the liquid is generally diluted 1:4-1:3. It should be noted that if the developing temperature is set too high, the developer will evaporate and oxidize. The speed is too fast and fails, resulting in excessive film fog, while the high density is not up to the requirements. The recommended temperature is 34-36°C, and the density and linearity are measured again when the development temperature is stable and the set temperature is reached.
(2) Other conditions remain the same, the higher the fixing solution concentration, the higher the temperature, the lower the film base fog (low density), the dilution ratio of the domestically produced fixing solution is 1:4, too high fixing temperature setting (or excessively high temperatures in summer) can cause the fixing fluid to fail due to evaporation or oxidation too quickly, resulting in excessively high film haze. At the same time, the high density may not meet the requirements, and liquid crystals of the liquid may adhere to the fixing roller. The film is scratched, so the fixing temperature is recommended to be 28-32°C and the fixing time is 30-35 seconds.
4. The laser photocoiling film contains an anti-halation layer. In the process of fixing and washing, some of them will fall off, forming a light blue water spot on the film base, which can be eliminated by adding an appropriate amount of hardener in the fixing liquid. The washing tank must be kept clean. After the work is completed, the water in the sink should be drained and wiped with a clean gauze. Before each water addition, remove some water to remove rust, and at least stick to the water roller once a week.
In a word, in the process of using laser to illuminate the film, only by grasping its characteristics and correctly outputting the output technology and operation technology, can effectively ensure the quality of the laser image-discharge and improve the output efficiency.
According to the different characteristics of the light source of the imagesetter, the laser photofinishing film is generally divided into two types, namely HN and red laser LD. The direction of the film side is divided into inward or outward, and one phototype machine can only use the inner or outer roll. One of the films. The film used in the conventional phototypesetting machine has two types of axis size, the small axis is 2.0 inches (51mm long) and the large axis is 2.8 inches (71.9mm long). Soft and hard flange refers to whether there are black hard plastic plugs at both ends of the film. Generally on the same photosetter, the hard and soft flanged films can be used interchangeably.
Each imagesetter can only use film whose width is smaller than its maximum size. The length of the film that the imagesetter can install is determined by the size of its cassette.
Photographic film in use should pay attention to the following questions:
1. Although the ordinary photocopying film is a bright room film, the loading process can be completed under the indoor light source, but in the actual production, the operating rules should be strictly observed, and the film is loaded into the loading box as required, and the cover is mounted on the stage. , Tighten the screws on both sides of the top of the box (note that both sides are balanced with equal force) and then tear off the film lead so that the film exposed at the film exit is parallel on both sides, the width of 1.5-2cm, in the process of handling to support The bottom of the box prevents exposure of the film due to shedding.
2. Before each batch of laser illuminating film is put into use, basic density testing and linearization of the dot network should be performed. Then, corresponding technological measures are taken according to the test result, such as adjusting the laser focal length, exposure amount, and the temperature and time of the developing and fixing. In order to achieve standardized and scientific production, prevent the formation of non-lattice products.
(1) Film density is divided into high density and low density. Low density refers to the density at which the film is completely unexposed after rinsing, typically around 0.05. The lower the low density, the more transparent the film is and the better the quality of the printing screen. High density refers to the density of the film after it has been washed at 100% exposure. The printing film used in traditional coated paper requires a high density value of not less than 3.5, usually 3.5-4.5, which ensures that the image information on the film is well transferred to the printing plate during printing. When printing on newsprint and offset paper (including map paper), the high density of the paper may be appropriately reduced due to the strong ink absorption and high printing speed.
(2) Linearization refers to the process of color separation. It is required to ensure that the dot values ​​set in the computer can be truly reflected on the printed film. Take 50% neutral ash as an example, where 50% of screen points are required on the computer, the output must be 50% on the printed film, and the dot error should not exceed 1% of the soil. Otherwise, the distortion of the printed image will be caused. This is especially evident in color four-color printing. However, film development, the stability of the fixing conditions is difficult to guarantee, so the more rigorous approach is to test the linearization every day.
3, the desk adjusts the concentration temperature of the fixer and the fixing time.
(1) Other conditions remain the same. The higher the developer concentration, the higher the temperature, the higher the density of the film. If the film is washed with a domestic developer (eg Aibisi SH-1000), the liquid is generally diluted 1:4-1:3. It should be noted that if the developing temperature is set too high, the developer will evaporate and oxidize. The speed is too fast and fails, resulting in excessive film fog, while the high density is not up to the requirements. The recommended temperature is 34-36°C, and the density and linearity are measured again when the development temperature is stable and the set temperature is reached.
(2) Other conditions remain the same, the higher the fixing solution concentration, the higher the temperature, the lower the film base fog (low density), the dilution ratio of the domestically produced fixing solution is 1:4, too high fixing temperature setting (or excessively high temperatures in summer) can cause the fixing fluid to fail due to evaporation or oxidation too quickly, resulting in excessively high film haze. At the same time, the high density may not meet the requirements, and liquid crystals of the liquid may adhere to the fixing roller. The film is scratched, so the fixing temperature is recommended to be 28-32°C and the fixing time is 30-35 seconds.
4. The laser photocoiling film contains an anti-halation layer. In the process of fixing and washing, some of them will fall off, forming a light blue water spot on the film base, which can be eliminated by adding an appropriate amount of hardener in the fixing liquid. The washing tank must be kept clean. After the work is completed, the water in the sink should be drained and wiped with a clean gauze. Before each water addition, remove some water to remove rust, and at least stick to the water roller once a week.
In a word, in the process of using laser to illuminate the film, only by grasping its characteristics and correctly outputting the output technology and operation technology, can effectively ensure the quality of the laser image-discharge and improve the output efficiency.
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