The hottest PDF cure for chaotic digital files

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Pdf cures chaotic digital files (Part 1)

managing and maintaining data flow is the most challenging work in today's printing industry. Whether it is silk printing or output to digital color printing machine, the efficiency and accuracy of printing work largely depend on how to manage and transmit digital documents in the whole process

when converting analog originals into digital documents, we are faced with many chaotic and complex digital processes and digital elements, and the process of generating and transmitting documents is also very error prone, making the management and transmission of digital documents the most ideal link in printing work

I. common problems

1. Font problems

include the loss of printed fonts in documents, inappropriate font replacement, inconsistent spacing between characters and symbols, symbol placement problems, differences in the structure of fonts provided by major software developers, and differences between font types (such as postscript, true type, multi to enter the modified plastic industry Master). As of 2010,

2. The processing of complex images

the processing of complex image files containing multiple elements and layers is a headache. When saving and transferring documents, it must meet the requirements of the designer and include all image contents and elements of the design manuscript in the document. When processing the classification and safety device files of the electronic tensile testing machine shared by the editor, it is often found that one or more images that should have been included in the electronic file are missing or need to be updated. When the elements in the design manuscript are changed, the document connection path may also be lost. Therefore, the image seen only from the display screen is not enough to ensure the correctness and integrity of the original. The more image elements in the original, the greater the chance of error

even if the various elements of the image are handled carefully and correctly, there will still be some unexplained problems when the image file is transferred to the imagesetter or digital printer, such as image movement and deformation. Sometimes, the root cause of this problem is that the version of the application software used to create the original file is inconsistent with that used to open and output the file. If you want to import vector image files of illustrator or freehand into Photoshop, problems often occur. For example, the imported EPS bitmap image is lost for no reason. In all these cases, what the traditional method can do is to check whether it is consistent with the original through printed matter or output film

3. File transmission problem

sometimes electronic files need to be transmitted through e-mail, Internet, modem (modem), and we don't know whether the files transmitted to the other party can be opened and whether the transmitted contents are complete and correct

4. Problems in compressing and decompressing files

problems are also prone to occur in the process of compressing and decompressing files. If it is lossy compression, it cannot guarantee that the image quality has not been damaged. It can be seen at a glance only when the color separation film or color print comes out. Often, a series of compression methods may be used for an image. When you open the file to decompress, of course, you want to decompress the file in the opposite order using a similar method

today, image files are getting larger and larger, and transferring files has become a "bottleneck", especially large format color images, which can reach 450MB or even 1GB. In addition, although fractal compression method is a feasible lossless compression, it still faces the problem of reading from magnetic media or optical media

5. Incompatibility between platforms

in the past few years, the incompatibility between MAC, PC, UNIX, workflow and personal systems has rarely been mentioned, but it really affects the work efficiency before printing

adobe PDF workflow came into being under this background

Second, PDF can solve the above problems

PDF is a platform independent file format, which is suitable for various data compression methods. It can transfer files between different platforms, networks and the Internet without worrying about whether the file content is distorted. Using PDF file format, the previously mentioned problem of turning off Fonts is solved. The imported image file will not make any errors in the whole prepress processing process. In short, using pdf7 1 software operation manual; Can realize the real sense of "what you see is what you get"

III. PDF file compression

pdf workflow converts continuous tone images, vector images, bitmap images and fonts into postscript code, and then uses spacer compression and code to convert the file into PDF format. The resulting PDF file is much smaller than the file before conversion

an important feature of PDF is that the compression of file information is convenient and flexible. Can I use different compression levels for the same file? Compress different types of data so that the file is as small as possible, and the quality of the image is little or no affected. The compression menu of acrobat provides four compression methods: JPEG, LZW, zip and run length encoding

jpeg: this compression method has five optional compression levels, which is a lossy compression. The greater the compression degree, the more the loss of image quality. JPEG can provide the maximum compression ratio, so the file can be minimized. JPEG is suitable for data compression of continuous tone images

lzw: this compression method is lempel-ziv-welch (LZW) data compression algorithm. It is a lossless compression, suitable for original compression with single color, and is also an ideal choice for vector image compression. LZW is not suitable for continuous image adjustment because the file generated by LZW is large

run length encoding: this method is suitable for compressing monochrome residences. The most common example is compressing black-and-white text files. Run length encoding is a lossless compression that generates smaller files

postscript images include color bitmap, gray bitmap and monochrome bitmap. With acrobat, different compression methods can be selected to compress different types of images. In acrobat, we can also set the down Sanping resolution value (depending on the specific application), and set the automatic selection or artificial selection of the compression method. It must be noted that different types of images have different compression levels

(to be continued)

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