Summary
In the current situation, the English PDF file format can be said to be very mature on the Internet and in the application of file exchange. However, the Chinese application has more problems than other Asian countries, resulting in its application. The scope cannot be universal. The main purpose of this paper is to explore the composition, production, and post-production file characteristics of the PDF file format. It is a test and discussion method.
Preface
The PDF file format developed by Adobe Corp. appears in front of us with the slogan "Intertextual, Cross-Language, Cross-Platform, Cross-Media, Cross-Software, Cross-Century Electronic Document Exchange Format" and "This is the Future." Such a document, in the end there is something special, what is the ability?
What is a PDF file?
The so-called "PDF portable file format" is an open electronic file format (according to Adobe's Acrobat PDF standard). It can be converted to "PDF" format almost no matter which computer platform or application software is used for editing. Interoperability. In addition to viewing the screen in exactly the same style as the printed effects (text, graphics, images), a variety of annotation tools are provided to allow users to read documents more efficiently. Usually we consider Acrobat and PDF as the same thing. PDF is the abbreviation of "Portable Document Format". Its main purpose is to create a common file format on various computer platforms. In other words, it is hoped that no matter what kind of documents are produced on that type of computer, as long as they can be converted to PDF format, they will be able to open readings without difficulty on another computer, and they will be able to maintain the format and layout at that time. It looks exactly the same as the original format. This problem has existed for a long time between different computer platforms. Files that are often created on PCs are obtained on the MAC. If there is no equivalent software or version, even if the software is the same, the versions are different or the Chinese and English versions are different. There may not be any way to open each other's files, causing considerable inconvenience. With the advent of PDF format, you can make a file on different platforms and look the same. You don't have to make any effort to transfer the file format.
å, PDF file format introduction
The Portable Document Format portable file format is a database that refines difficult-to-process PostScript code into a page and object. It contains fonts, images, and compressed vector objects. It is a highly streamlined file format. Just as its name-portable file format-is optimized for a unified predictable high-quality output and can be used for multimedia applications. PDF has device and media independence features that support CMYK, special colors, and merged color gamut definitions. PDF is a file that supports trapping, imposition, and convertible page orientations. Most people can use the free Acrobat Reader software to browse Macintosh computers, Windows environments, Unix and Internet browsers.
There are many kinds of procedures for making PDF, and many PDF files of different natures and different uses can be produced. For example, one of the methods is called "distillation". Adobe Acrobat Distiller software can be used to convert Postscript files into PDF files. In addition, Adobe PDF Writer, a tool for selecting peripherals, can be used to store files automatically. It can be converted into a PDF file by using a Postscript file, or a single or multiple Postscript files can be converted into PDF files by using program macros or other automatic functions. In the previous prepress workflow, if the customer needs to make a last minute change, he needs to go back to the original editing application and reprint it once. In the PDF workflow, he only needs to use Acrobat to directly modify the PDF file, no longer Go back to the original editing application to modify the print.
One, PDF file composition
1. The first layer contains the text and images of the file.
2. The second level contains synergies, such as bookmarks, hyperlinks, navigation, etc.
3. The third layer contains the basic information of the file, such as font information and exchange reference tables.
Second, the characteristics of PDF file format
PDF is Postscript's post-purification file. It has removed the uncertainties that Postscript may have when interpreting it. After successful conversion to a PDF file, it will ensure smooth progress in the subsequent workflow. You can convert any application generated page into a PDF file, complete the text, graphics, images, sounds and links of the original file embedded in the PDF file, so that you can make edits at the last moment without having to return to the application Program modified to print. When converting, you can choose to wrap the text into a PDF file. Even a Chinese PDF file can be properly printed in a plain English system without a Chinese font installed. The true goal of a file exchange network is to have no borders. The PDF can also be converted into an EPS file containing fonts. The converted EPS file can then be reassembled or imported into other software for reuse.
(a) high compression
PDF files use multiple methods to achieve the purpose of reducing the original Postscript file. In the compression part of the picture, the format can also be compressed, and the general file can usually be compressed to tens to one-hundredth. Especially when users want to distribute electronic files on the Internet, high compression ratios are particularly important for speed considerations.
1.JPEG: The Joint Photographic Expert Group's Professional Photographic Association, which promotes a degenerate static image compression algorithm, compresses the image quality for a destructive compression method. Its application range is for color continuous tone images. More suitable.
2.Zip is developed with extensions of the Zlib suite software of Jean-loup Gailly Mark Adler. The compression method is suitable for pattern, shading or large-format repetitive image files. Acrobat 1.0 provides 4bit and 8bit different compression ratio algorithms. The sampling method is based on repeated data.
3. CCITT Group1. CCITT Group4 is a compression standard set by the International Coordinating Committee for Telephony & Telegraphy. It is used to compress black-and-white graphics software, or monochrome scan images and line art. . Acrobat 1.0 offers these two compression methods for single-tone linework, such as fax quality files.
4. Run length is for the compression of monochrome line art, especially with a large area of ​​monochrome color image files.
5. Compress text & Line Art Text and lines can be compressed. <Note 1>
(II) Equipment independence
General Postscript files contain many possible legitimate code that may not work under certain conditions. For example, those that rely on certain special font structures, or output devices. On the contrary, the PDF format does not contain any program structure, which makes it more secure and more suitable for storage or transmission in the form of electronic data. PDF is designed for networks that integrate multiple output options. It is a standardized and device-independent optimized output format. For Chinese PDF documents, when Chinese systems are not used, Chinese can still be displayed independently; when using Chinese systems, Chinese vocabulary can be searched.
(å) Each page is independent
The pages of a Postscript file are related to each other. This means that you must deal with all pages in front of it before jumping to a page. The PDF format does not have this limitation. You can read any page of a PDF file directly without having to consider other pages.
(4) Notes
PDF files can contain a variety of annotations - such as bookmarks, miniatures, links, notes, text strings, logos, and media boxes. You can use these "notes" to improve the quality and readability of your files. These "notices" can also effectively assist in file management work - such as production, sending, endorsements, amendments, final drafts, and publications.
(e) file protection
PDF files can tolerate passwords and other protections to prevent illegal use. For example, a password must be used to allow reading, permitting, or not allowing printing, copying, endorsement, or modification.
肆, Chinese PDF file production process
First, the web format PDF file format transfer:
The PDF file has been easily produced in the production of English fonts, but it is still not easy to convert web pages directly into PDF files before the Chinese language part is entered. It is necessary to rely on some conversions to turn pages into PDF files indirectly. In the current situation, the function of opening a web page in Acrobat 1.0 can only be used on an English web page. Simply using Web Capture to input a URL can convert an English web page into a PDF file and retain its hyperlinked portion. Format. However, in the Chinese webpage section, Chinese fonts will become garbled. Therefore, PDF files must be printed using the Acrobat writer and Distiller. Although the hyperlink format cannot be retained, hyperlinked forms can be set.
Second, typesetting software transfer PDF file format:
At present, the common typesetting software does not support the PDF file format directly. Most of the typesetting software cannot directly transfer PDF files, but must be printed by printing. The Microsoft Office series is the most complete software that supports direct dumping of PDF files. Basically, you only need to install Acrobat 1.0 after Office to create an Icon on the toolbar. Users can click directly You can start a PDF Maker program and easily convert files to PDF files. Others such as Page Maker, Quark Xpress or Illustrator must install plug-ins to transfer PDF files directly. Basically, a variety of software-generated PDF files containing Chinese fonts can be roughly divided into the “Acrobat Writerâ€, “Acrobat Distiller†and “curve†types of production methods, in which the largest file capacity is converted to curves. Followed by Distiller, the smallest is generated by Acrobat Writer. When the software is generated in the same format and the software used is not the same, the size of the file will be slightly different due to the information contained therein, but the characteristics of the file are the same.
Its general production process is as follows:
å, PDF file format is output when the workflow:
The PDF file can be used with Postscript 3 RIP for maximum productivity in professional output. Because Postscript 3 directly supports PDF file format, when the file is printed to Postscript 3 RIP, RIP only needs to process the network, so the processing speed is relatively Improve and print quality (eg, gradient). And if your original RIP only supports PostS
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