Precautions for the hottest plane output printing

Notes on plane output (printing) (6

6. Lithography principle

there are several printing methods in printing, such as lithography, relief printing, intaglio printing, etc. at present, relief printing is used in books, newspapers and packaging printing in China, while foreign relief printing has been replaced by lithography. Compared with relief printing and intaglio printing, lithography printing process has its own uniqueness, which is summarized as follows:

1) The practical application of the natural law of immiscibility of oil and water in lithography. Lithography uses the law of immiscibility of water and oil to achieve the purpose of printing. At present, lithography is still inseparable from water

2) For a lithographic printing plate, the blank part and the graphic part are almost on the same plane of the printing plate. Using the law that water and oil are immiscible with each other, through technical treatment, the lipophilic and hydrophobic graphic part and the hydrophilic and hydrophobic blank part are formed on the same plane of the printing plate. In the printing process, the wetting mechanism first applies a uniform amount of water to the blank part of the printing plate, which does not adsorb ink, and then the inking mechanism adsorbs an appropriate amount of ink to the graphic part, which completes the transfer and reproduction of the graphic through the imprinting mechanism, so as to achieve the purpose of printing

3). The way of lithography is an indirect printing. The graphics on the printing plate are "regular". The ink on the lithography plate is not directly transferred to the paper, but first transferred to the rubber drum, and then transferred to the printing material. Therefore, its graphics and texts are "regular", which belongs to indirect printing. The rubber blanket wrapped on the surface of the rubber drum has two characteristics: first, it has good hydrophobic and lipophilic characteristics, which can fully transmit ink and limit the transmission of water

, and second, the rubber blanket is elastic, which can print an imprint with small expansion rate of solid surface under the condition of large printing pressure and reverse inclination of the working platform (no more than 2 climbing heights of 6cm at a time) compression deformation

4). Dot matching -- the colors presented by lithographic products are ever-changing and beautiful. The formation of their colors is formed by overlapping dots and color ink, and dot matching is the main. It is guided by the light color theory, uses the means of dot overlap and juxtaposition, and uses the theory of three primary colors or three primary colors plus black (four colors), through photographic color separation or electronic color separation, decomposes the colors of the picture into four color plates with different grain angles, such as yellow, magenta, cyan, and black, Then use four-color printing plate and overprint to reproduce countless layers and colors, and obtain artistic copies with very rich colors

5). Multicolor overprint, printing a wide range of formats -- lithography can print monochrome text, but mainly multicolor overprint. Printing format (2) according to the size of the experimental workload, it can be large or small (four open - double full sheet) and can print dot and field multicolor products at the same time. The finished image is flat and bright, which is better than other printing methods. The graphic part and blank part of the lithographic plate are on the same plane, which have completely opposite properties to the affinity between water and oil. The graphic part is lipophilic and hydrophobic, while the blank part is hydrophilic and hydrophobic. The function of the graphic part is to absorb the ink and repel the fountain solution. In the printing process, the blank part is first wetted by the fountain solution, then the graphic part is coated with ink, and then the ink of the graphic part is transferred to the paper. Lithography is based on the principle of immiscibility of oil and water to transfer the pictures and texts on the printing plate to the paper

7. Simplified EPS image

if we want to say the final reason, in the postsript file, the overly complex path is the culprit that makes the file unable to print correctly. The path with too many nodes or the smoothing setting is too low will increase the complexity of the file, cause the laser printer or imagesetter to crash, and lead to a fatal "limitcheck" or "vmerror" postsrip error. In particular, when sending files to high-resolution output devices, you should split complex paths and set high smoothness in illustrator or Macromedia, or use the instructions in eehand to simplify paths. When using Adobe streamline tracing, path simplification is used to reduce the complexity of the path. Use high tolerance reading values in Photoshop to reduce the number of nodes when the selection becomes a cut path. Do not insert EPS images into other EPS files. Like this: input several EPS images into the illustrator file, store them as EPS, put them into a QuarkXPress page, store this page as EPS, and then put them into another QuarkXPress file. If you are lucky, that document can be printed just as the piston of the oil cylinder rises gradually. However, as each layer is placed into EPS, the chances of success will be less and less. If you have to convert a full page of QuarkXPress EPS into a file that can be used by Photoshop lattice. Let Photoshop change the file into a dot matrix image, and then store it as EPS or TIFF of Photoshop. Neither of these formats adds an extra layer to the postsript language

8. Smooth the gradient

the gradient using the mathematical operation method made by QuarkXPress and illustrator works well in a short distance of a few inches, but if you try to make a subtle gradient of the whole page, the limitation of postsrip may lead to a banded effect. Make the gradient into a dot matrix image in Photoshop (use add noise), and then input it into other applications. However, Photoshop cannot be used to deal with layers made in illustrator. Compared with the gradient generated directly in the Photoshop palette, the illustrator file processed by Photoshop cannot produce an ideal intermediate gradient

9. Use good fonts

many output centers don't want to see TrueType words. Postsrip has become a standard. TrueType usually has the same word name as the corresponding postsript word, which will cause conflicts. TrueType must be manually downloaded to the rip of the Imagesetter, which is time-consuming. Contact the output center in advance. Do not use font commands to produce bold or italic effects. It is best to select the desired font effect directly from the font menu of the application software. If the font does not have the desired bold or italic effect (1) coaxiality, and the font command is used, the Mac will fake bold or italic effects for each word -- but this is only on the screen. If it is output on the printer, the final printing effect looks like it has not been used at all. So, what is the effect of using the bottom line? Don't use fonts that have no effect on their own, but need fonts with font commands. If you use a font with beautiful serifs or fine strokes (Bodoni is a good example), and the size of the word is set to be very small, do not separate the color of the word. Otherwise, even if the alignment on the printing plate is slightly misaligned, it will cause inaccurate overprinting of the most sensitive parts