Process of printing plate making

Third, what is the difference between DPI and LPI? DPI is the number of dots per inch, which is used to represent the processing accuracy of the image processing system. It is one of the units that measure the resolution of an image. Generally, 2*2 pixels or more correspond to 1 dot, that is, the number of lines per inch of the LPI screen. It is about one-half of the DPI number; the scanning spot constitutes one dot, that is, the number of DPIs must be more than 10 to 20 times more than the LPI number. Fourth, what is a pixel? Resolution? Pixels are the smallest unit that describes the image in a lattice. Although the pixel is the smallest unit describing the bitmap image, it has a fixed shape but does not have a fixed size. Resolution, representing the image processing settings to represent the fineness of images and prints. Fifth, what is the color has nothing to do with the device? The result of image color data obtained by a certain kind of image processing device should be able to be restored accordingly on another processing device. six. What is color management? What are the contents of color management? There is an interoperable problem between different software or hardware, how to obtain the expected consistent color under a variety of configuration possibilities, that is, study device-independent color representation, and the conversion of color representation for a specific output device. . There are three major aspects of color management: corrections, features, and transformations. 7. What is computer direct imaging printing? Direct-imaging printing is a new technology for computer typography. When this new technology is adopted, it does not require the traditional process of producing PS plates through output films and film, but uses color desktop publishing systems to edit graphics, photos, and texts. After the images are processed together, the images are directly presented on the printing plate for printing. This printing method can obtain a resolution of as many as 175 lines per inch of color print on the same line. 8. What is the technical basis of the color desktop publishing system? l. Graphical user interface (GUI) and "What you see is what you get" idea. 2. The use of page description language Postscript. 3. The use of PageMaker for Macintosh computers and laser printers and layout software that can output Postscript. 9. What is the most open system? Can accept any kind of Chinese system input file, can be output to any English software for processing, the results can be sent to any kind of output device machine electronic color machine, laser printer, laser imagesetter, computer voice painting In the drawing machine, computer cutting plotter, etc., can also be output into a PS file, get any output center in the world to output four-color CMYK color separation film, this is the concept of full open. Postscript language is the basis. X. What is the role of Postscrip? What is the most characteristic? Role: PostScript language is the interface language that most desktop systems output to photo-set devices and is designed specifically for describing images and text. A variety of desktop software systems work together and must rely on a certain format to exchange information with each other. This is the Postscript language. The function is to record the image text on the page with a digital formula and run it on a computer. Finally, it is translated into a desired output by a Postscript decoder, such as being displayed on a screen or output on a printer or an imagesetter. The Postscript file is just a text-based file that can be used on different computer workstations such as MAC, PC, NEXT, SUN, etc. Features: l) Ability to comprehensively process text and images 2) Basics of open color desktop publishing systems: With the Postscript standard data format, data is possible between general-purpose computers and various special-purpose computer systems produced by different manufacturers. exchange. 3) Avoid the dependence of layout on the use of equipment. 11. What is the role of RIP? The role of RIP is to convert the lines, curves, and images created in the Postscript application software into commands for bitmaps with the appropriate resolution, and to control the output of the laser spot by the laser recorder as a switch. "Yes" and "None" output the formatted results to the film. Twelve, what is OPI technology? OPI is an annotation specification based on the Postscript language. These annotations specify the relevant geometric parameters of the high-resolution file, the location of the save and the parameters related to the communication network. OPI can manage a large amount of image data in a centralized manner, generating a dedicated workstation with OPI annotations and display representations, and performing output management and image substitution functions, commonly called OPI servers. 13. What is the workflow of the color publishing system? l) Text entry: Enter the text into the computer. 2) Scanning the image: The image is digitized and entered into the computer. 3) The group Z edits and modifies text and images on the computer and then edits the text and images, and prints the proofs of proofs. 4) Color separation exposure: After the profile image processor is used to describe the page description language of the layout into a dot matrix image, the dot matrix image is sent to a laser imagesetter to control the sensitivity of the film. 5) Rinse: After the film is sensitized, use the punching machine (developer) to flush the color separation film out of the four-color film. 6) Print Proofing: Provide proofs and proofs for printing reference. 7) Finish color prepress processing. If the material used for separation in the fourth step is PS (pre-sensitized plate), this workflow is called CTP. XIV. What products are generally included in the product quality inspection before export? How to adjust the imager's output characteristics? What are the labels on the output film? Pre-export quality inspection items: 1. File inspection before output (check of laser proofing) 2. Check layout and finished product size. Single-P or dual-P output problems and verifiable bleeding sites. 3, color map placement and cutting. l) Confirm whether the figure is in a horizontal position, especially the visually obvious pictures such as the architectural building diagram, the connected map of Haitian, and the vast plain map. 2) Confirmation of the quality of the bottom of the picture; whether it is refunded as required. No leakage or retreat phenomenon, the land should be sleek. 4, text confirmation: the correctness of the text to reach 100%. The text is big, clear, complete, clear, correct, and correct in color. 5, color blocks, color strip color confirmation. 6, picture blur and gradient quality confirmation 7, spot color color and color sequence confirmation. 8, require the confirmation of the revised part. Laser Imager Output Characteristics Adjustment: * Imagesetter output is composed of halftone dots. The key to the calibration is that the size of the film internet point (ie, the concentration of the area dots) should be exactly the same as the dot size of the scanned image and the dot size specified in the application software. * Tools: Density ruler, anti-permeability instrument. * Output exposure test: Objective To find an optimal exposure to set the exposure of the output machine to ensure that the imagesetter output can provide the necessary concentration without causing serious halftone errors. * The method is: first use the imagesetter to produce a page composed of straight lines generated at different exposure intensities. After the page is developed, only the exposure results are measured with the density, and the best value is selected. *Whenever changing the important variables, such as table materials, chemical liquids, etc., should be tested once. What are the label on the output film, the crop mark, the adjustment bar, the density scale, the file name, and the color name. 15. What are the parts of the Mac desktop? It consists of three parts: icon, window, Leister XVI, role of SCSI interface and connection rules. Role: Connect the edges of the computer and external devices. Connection rules: The address lines are only 0-7. Each device is connected in series. There is a finalizer at the end of SCSI. 17. What is the difference between a stroked word and a lattice word? Stroke words can be divided into POST, digital description of the way, can be arbitrarily zoom in and out for the screen display, zoom in and out will be deformed eighteen, what is a vector image, what is the most bitmap? The image is represented by a mathematical formula. Bitmaps are represented by pixels. <DT7> production requirements: (To sell as a standard for printing) l. Determine the size of the finished product and the size of the blank area on the finished product: If the above dimensions are determined incorrectly, invest a lot of time and energy to complete the work. After that, you will have to face the fate of re-doing completely, because the workload of the revision may be much greater than the amount of work to be redone. Bleeding position: All future objects on the finished product close to the position of the cutting edge should be placed at least 3 mm beyond the cutting incision. Only after the future cutting will the effect of the object closely adhere to the edge of the finished product; ie, the object ( A small part of pictures, graphics, text, etc. will be cut out. This is called "bleeding." 3. Image format: Pictures refer to images and graphics. Various types of pictures in computers are divided into two categories: Images (also known as raster images, bitmaps, and pixel maps): are pictures that consist of one pixel, most Common is the scanned photograph. The image is processed with specialized image processing software such as PHOTOSHOP. Graphics (also called vector graphics): It is composed of mathematical descriptions of diameters and curves. They do not exist by themselves. They are only created by specialized graphics processing software, such as those created by the drawing softwares such as FREEHAND, COREDRAW, and ILLUSTRATOR. Graphics are vector graphics. The above two types of pictures do not ask the essence. Please pay attention to understanding and distinguishing. The correct picture format should satisfy the following conditions: no loss of file information, small electronic file size, high efficiency when the film is separated from the film, and good versatility (acceptable by most output centers and application software). For images composed of pixels, the most common format is TIFF; for graphics, the most common format is EPS. 4. The resolution and color space of the image: In order to achieve the effect of printing level, the resolution of the image should be the number of lines added during printing. 5-2 times (refer to 1:1 ratio, that is, the picture should not be enlarged or reduced again). For example, now that the color print is generally 175 lines/inch, the resolution of the image should be 30 ODPI or 35 ODPI after the size of the image (length and width cm) is determined (the number of 327 should be taken, and a multiple of 50 is better) After confirming, after inserting the typesetting software, it is in principle required to no longer be able to zoom in or out. If it is not possible, there may be 10%-20% scaling. When the image is sent to the photocopy, it should be converted into CMYK color first. Do not use other color spaces such as RGB. All layers and channels should be removed when the image is stored last. 5. The size and color of the graphic: The size of the graphic should be determined according to the size of the final printed product. Do not zoom in or zoom out after placing the typesetting software (this will increase the output time of the phototype). The color of the graphic is generally marked with the CMYK color (this way The actual color after printing can be expected.) 6. Text: If the text does not need special effects, it can't be printed with image software such as PHOTOSHOP. It can be used as an image and then put into typesetting software (words printed in this way, the edges are imaginary); the text should generally be entered in the typesetting software. You can type in the graphics software. When the graphic containing the text is output in EPS format, you can choose to convert the text into a graphic option. 7. Registration problem: too small colored text or graphics (such as a fine line), if you need more than two kinds of four primary colors overprinting two, it will not appear because 100% of the color version can not be reprinted together and appear fuzzy clear. Therefore, small text or graphics (including colored text, graphics, or colorless text, and graphics printed in two or more color backgrounds) should be as monochromatic as possible. 8. Overprinting and Trapping: 9. Submit documents before sending to the output center: (taking PAGEMAKER as an example). (1) Insert a graph in PAGE MAKER. When the graph is small (such as tens of K or less), the graph can be completely set. That is, the graph is completely included in the PAGE MAKER file. The original graph can be lost; but when the graph is smaller When large (such as several hundred K, several tens of M, or hundreds of M), if the graphics are completely in person, the PAGE MAKER file will be too large to be manipulated and controlled, so when you put the image of the electronic size is greater than PAGE When the value set by MAKER is reached, the last query box will appear: Is the least included in the PAGE MAKER? You should choose "No" at this time. In this way, PAGE MAKER only places a low-resolution pre-view that is obtained from the original but smaller than the original image. You can manipulate this view. The position of the view completely represents the original image. This is called “Link. ". (2)PAGE MAKER