Q & a 4 of the hottest color desktop publishing te

2022-07-30
  • Detail

Q & A on color desktop publishing technology (IV)

1. what is postscript language? Postscript is a page description language developed by Adobe in 1985 on the basis of a previous 3D graphics oriented language. It is an interface language output from desktop systems to Phototypesetting devices. It is specially designed to describe images and words. The function is to record the image and text on the page with the method of digital formula and run it on the computer, and finally translate it into the required output through the postscript decoder, such as display on the screen, or output on the printer and laser Imagesetter. Postscript language is the most popular form of page description language in the world. It has a large number of graphic operators that can be used in any combination. It can describe and process text, geometric graphics and external input graphics. Theoretically, it can describe any complex version. The success of its design using this page description language has become the choice of many manufacturers. Its rich graphic functions and efficient description of complex pages have attracted the support of many publishing system typesetting software and graphic software. Almost all prepress output devices support PS language. The success of PS language also makes the open electronic publishing system widely popular in the world. It also became a de facto industry standard in the late 1980s. After years of experience and feedback from many PS products, PS2 was launched in 1990, and then PS3 was launched in 1990. 2. how is the gray level of the output device calculated? High grade DTP systems are usually equipped with laser imagesetters with output resolution above 3000dpi. The gray level of the output device can be calculated according to the following companies: the gray level of the output device = (output resolution/number of lines) 2+1 if the output resolution of the laser Imagesetter is 2400dpi and 150lpi is used, the output gray level can be 255. The gray level that can be distinguished by human naked eyes is about 140. It can be seen that the 255 level greatly exceeds this range and fully meets the requirements of high-end products. The above company can be rewritten as: output resolution =sqrt (number of gray levels -1) * number of lines. According to this formula, we can calculate the closest resolution to meet the requirements, so as to optimize the output time of the imagesetter. 3. what is digital proofing? The traditional proofing is to use the negative or positive image to sun the printing plate, and then use the printing plate to proofing. In recent years, due to the progress of computer image processing technology, the color desktop publishing system and color electronic prepress system integrating text and image processing have developed rapidly in the field of professional printing, and there are more and more requirements for the corresponding digital proofing system. The digital proofing system is a proofing system that uses prepress data and does not produce 3D printing materials subsidiary ninjatek of finner group, UK, before producing negative or positive images. Recently, ninjatek announced that it would release "cheetah" and "pangolin" raw intermediate media films worldwide, but directly produce proofs in the form of digital output. It is a kind of proofing method that directly outputs digital color image information on paper by dot tone or other methods to simulate the printing effect. Digital proofing includes silver salt photography, inkjet printing, thermal sublimation and color laser printing. 4. what is rip and what is the basis for measuring rip performance? Rip is an abbreviation for raster image processing. As a noun, it refers to the hardware or software that translates PS code into dot matrix image in the phototypesetting system. Commonly known as raster image processor. It plays a very important role in the electronic publishing system of color prepress system. Its function is to quickly interpret the page description language from the workstation or server into lattice commands that can control the output of the laser recording equipment. It will be an automatic electronic translator with good electrical insulation. It can automatically convert the text images, lines, graphics, etc. arranged in the computer software into lattice data of digital images, and then send these lattice data to the recording equipment, Like a switch, it controls the "yes" and "no" of laser spots, and outputs the arranged layout results to the film. The addition processing algorithm of rip and high-speed character restoration technology (including Chinese character processing) are the main basis to measure the performance of rip. Secondly, Rip's compatibility with file formats and multi-functional support technologies such as trapping and color separation have also become a very important indicator of rip. The verb meaning of rip may be translated into "raster processing" or "dot matrix processing". 5. What is the working principle of OPI? Regardless of the user system or operating platform, OPI is a relatively direct processing method. After an image is scanned or input into the computer with high resolution, it will be saved as a document file or image file. OPI operation program resamples the image to create a low resolution alternative image. This low resolution FPO image is usually saved in TIFF or EPS format according to the original image. In order to match most desktop monitors, FPO format images are often saved at 72dpi. Because the OPI sample generator can recognize multiple document formats, it is easy to create low resolution fpos format images for preview. Some of the original images can only be viewed with special application software. For example, some applications cannot read the shlw format or use TIFF images compressed by a CCITT compression format. The most commonly used document formats include tiff, EPS, dcsv1 and V2, Scitex handshake ct And JPEG (these are the minimum formats that should be supported by any OPI server). Some other formats include Scitex handshake LW, copy dot tips, and Photoshop mate. In order to make the typesetting easier, the designer takes the packaging box from the server and uses some small accessories to switch the FPO image, arrange, cut and rotate, and then save it. When the document is output to the PS device, two things will happen. First, OPI writes a series of contents that describe the position and characteristics of the FPO image on the page (crowding, scale, rotation), Also write down the name of the image and find the path of the high-resolution image in the server, and then the OPI image server converts the image and sends the large PS document to rip for processing and output. According to this system, the high-resolution document can be (1) mixed and separated with polyethylene and other chemical polymers in a certain proportion before being stored in the server; (2) It is separated by the OPI on the server (3) and saved as a composite file, which is separated by rip

Copyright © 2011 JIN SHI