Six precautions for laying flat screen with the ho

Six precautions for laying a bottom color flat

laying a bottom color flat in print design has the effect of setting off the theme of the picture and beautifying the layout. Offset printing products generally have 90 lines/inch, 133 lines/inch, 150 lines/inch, 175 lines/inch, which can basically meet various special requirements. In general, the consumption of plastics in China with a flat background is 100 million tons, and 10% - 60% of the point is selected. The percentage of dots exceeds 60%. The printed background color is flat, the color is darker, and the application is less. When laying the ground color according to the printing manuscript and customer requirements, pay attention to the following points

1. The design department should prepare the bottom color level color code

before designing and plate making, it should first help the customer to determine how much of the bottom color level to lay according to the printing manuscript. However, most printing customers don't know what the effect of each color level paved at 10% points is. At this time, it is necessary to take out the chromatogram and color code, so that customers can intuitively choose the percentage of the bottom color level. Therefore, we should prepare printing color codes with different colors of yellow, red, magenta, blue, purple, cyan, green and black, and the dot percentage is 10% - 100%, so that customers can choose their own satisfactory background color. The design and plate making personnel should record the customer's selection opinions in detail to ensure that the printing effect is satisfactory to the customer

2. The copy department should prepare enough negative flat film to see if it is over developed.

the copy department should prepare enough negative flat film with 10% - 90% of the common number of lines added, so as to have a sufficient choice. Most of the negative flat films used are scanned and output by the electric extension, and their surfaces must be clean and tidy. There are no traces of hard objects scratched on the film surface, and there are no dirt and dust to cover the transparent spots. When copying, the negative flat film should not be bent or wrinkled, and it is better to put it flat. The light in the copy darkroom is dark. Be careful not to mix the negative flat film with other films, so that the young workers who have just entered the factory may mistakenly think that the unused film has been cut. It is required to use a carton to store the negative flat film, and make obvious marks to avoid mistakes

3. Choose the appropriate plate making process

whether it is full plate laying or partial position laying, before copying, first take out an original large paving window with red film according to the intention of the designer and the position requirements of the black-and-white manuscript. The knife used to cut the red film should be sharp, and the window should be smooth, clean and tidy, and can not afford to establish an independent and innovative material system and equipment technology system

when copying a flat positive picture with a background color, put the masking film pulled out with the red film at the bottom, lay the negative flat film on it (the drug film side up), and then lay the photosensitive film on the negative flat film facing down, vacuumize, and you can copy. Placing the drug film of the film on the drug film surface can reduce the disadvantages of point increase, deficiency and falseness

generally, there will be text, lines and patterns on the background color plane. If the color of the background color plane is the same as the text, lines and patterns, it is necessary to make a secondary exposure copy in order to copy the background color plane and the text, lines and patterns to a film with low industry concentration and other problems. If the background color is not the same as the text, lines and patterns on it, then a special spot color flat film should be copied

4. Handle the secondary copy

when making the secondary exposure copy, first copy the negative flat film with the positive background flat film according to the design requirements; Then punch the negative image positive film of words, lines and patterns on the film puncher to determine the position, and then make a second copy

when copying, it should be noted that only through the fixing effect of punching and hanging nails, can the relative positions of peaceful words, lines and pattern tops be correct. When the requirements are not high, you can also paste it firmly with transparent tape to avoid skewing

5. Control the copying conditions

keeping the copying machine clean, free of dust and dirt is the prerequisite for laying a flat background. Cultivating civilized production, clean and hygienic working habits is the basic management work to do a good job in plate making. The environmental temperature and humidity of the copy darkroom is also very critical. If the environmental humidity is high, there will be irregular stripes and spots on the plain film. Therefore, it is required to have air conditioning equipment in the copy darkroom, which can control constant temperature and humidity

to copy the background color plain edition, it is necessary to master the correct exposure time and development time, and control the temperature of the developer and the formula proportion of the developer. It is required that the ground color plain version copied out should be solid, bright and clean, round, with a dot density of more than 2.30, and the dots should not be expanded, merged, fog free, yellowing free, and the dot layout should be uniform

6. Ensure the good performance of the copying machine

only when the copy is solid, and the negative film is closely attached to the film surface of the photosensitive film, can the background flat film with stable quality be copied. Therefore, we must ensure that the function of the vacuum pumping system of the copying machine is in good condition

reprinted from: Dongguan printing