DTP designer should pay attention to several issuesBecause DTP from the manuscript to four color film to all prepress work in computer; as the DTP run through from design to print all links as used in computer language to describe the electronic pages of pure mathematics, as distinct from Gan high-speed printing ink on paper such a physical process, so DTP computer designers to participate in first line of the printing plate.
this computer designers put forward higher requirements, outside of art design, asking them to require additional knowledge, in particular printing separations, screen, overprinting, imposition of knowledge and so on, so as to be able to reproduce accurately and truly original. First note separations
, net, and so on. Computer designers must be clear, in the process of printing is obtained by adding different amounts of cyan, magenta, yellow, and black ink in the form of dot overprint to a variety of color. We are close to watching a color newspaper, you can see that it is made up of many dots. In a dark place, larger; in the middle area, and point size; in a brighter place, is relatively small. However, the adjacent point is equal to the distance between the center of the adjacent Center decided to hang a picture on the screen, this distance is called the screen line number. Screen line number is generally expressed as the number of unidirectional parallel lines per inch. Newspapers used by screen lines per inch is typical of 80-100, magazines and other color printing is 120-150 lines per inch, albums of high quality art is 175 lines per inch, 200 line. Generally, he said, scanner color image resolution (DPI) value is output twice times the screen line number as a principle. If you want to print 150 lines of a magazine cover, then when scanning dpi value should be 150 X2=300 of the output image (DPI). Therefore, the designer should first understand what to print design work, is a newspaper or a book, to determine the picture scanning dpi value. Scanning dpi value is set higher, printing prints "Pappy", DPI value is too low, it works fine. Common values are: the carrier screen line scan DPI paper 80-100 150-200 Journal of 120-150 250-300 pictures 175 up to 350-400 in four color film, different colors of points arranged in a different angle, in order to avoid printing inks overprinting with different colors. Dot Center clip angle between the vertical line and the horizontal line is called the screen angle. In typesetting is set in this screen point, they use is carefully selected and ingenious compromise: cyan 15, magenta is 45, yellow is 90, black is 75. Some daring designers give them the default perspective of their own choice, it should carefully consider and trial and error, so as to avoid the network cable does not fit the "moire". In order to be able to reproduce the exact original dot Delta are problems that should be noticed. So-called net incremental print dot on dot size than the original design has extremely small percentage change, manifested in the Visual print shades of dark and light and color changes. Especially in the light. General points to the following stage increases.
1) imagesetter film outlets increase in the output 2) dot exposure film exposure increment 3) of printing ink dot increments, of course, the types of printing machines, paper types are also important factors of the network increases.
in order to be faithful to the original as possible, taking into account in the design and to overcome the network increases. Imagesetter outlets of incremental, you can overcome by periodic calibration output film dot. Can output a set of gray-scale screen on a regular basis, and density, and correct the setter of the set of values, this correction is very important. Incremental about 10% about
dot, design should be considered in the design of outlets than to get the actual network small 10%, to ensure that the prints can be faithful to the original. Is the best method for different printers. Different ink, after repeated experiments to determine the incremental percentage dot. And accurate when made to overcome them.