The hottest PDF and key issues in Prepress

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PDF and the key problems in prepress

analysis of the current situation of application

now, the adoption of PDF workflow in a certain range of black-and-white printing applications is no longer a new thing, and for some commercial printing, such as business forms, books and newspaper advertisements, PDF workflow is adopted. At the same time, PDF integrates EDI transaction management, job ticket and database application technology, which is a further development of PDF workflow of black-and-white printing in the future

color printing, which is relatively simple for users before measurement, has a slightly complex printing process, and does not require very high color requirements, has been well established on the PDF workflow, such as commercial form printing. Pdf is increasingly becoming the first internal format for on-demand color printing

PDF workflow has great penetration into color newspaper advertising, which is partly stimulated by the early adoption of color advertising schemes and industrial standards for EDI transactions. In developed countries in Europe and America, PDF workflow is becoming the workflow of magazine and catalog printing, but the primary condition is to provide a complete production scheme. Now, we see that PDF based workflow is moving towards more complex digital printing applications, which involve mass customization of page content or dynamic composition from databases

PDF workflow is gradually penetrating into color printing applications with high commercial requirements, such as offset printing, packaging printing and special printing. With the introduction of the integrated PDF production system, the commercial PDF production workflow will be developed by leaps and bounds

however, today's PDF aware applications have not yet made full use of the information architecture provided by PDF. Therefore, it is necessary to close the gap between channels. In a few years, this situation will be dramatically improved. Pdf application will become closely intensive, that is, integrating e-commerce, information management, process management and other activities

if we pay attention to the production activities at different stages in the printing communication channel, we will see that PDF provides an information system that supports the activities of the whole production cycle. From communication design to page generation to media production

e-commerce: the printing industry needs a very smooth and clear way to express and process transaction information. Whether PDF files are transmitted by e-mail, web or managed distributed services, relevant business functions must also be carried out in the network. The generation, establishment, management, tracking and termination of these transactions are carried out in a distributed production cycle. XML has emerged as a breakthrough standard and has been applied to electronic data transactions (EDI). Some EDI specific functions have been developed to meet the requirements of various fields in the printing market, including space for digital advertising; Prose (production order specification/edi) and bisac (book industry systems Advisory Committee) used in magazine publishing, the key to success in these industries is whether customers and businesses have the same attitude towards EDI

color management: color must be synchronized and consistent through equipment and display in the printing workflow, and color management will develop into a service realized through network. Within the network workflow, the color management system (CMS) enables different or remote output devices to achieve color consistency. The current version of PDF does not support its own built-in ICC profile, but pdf1.3 and pdf/x will fill this gap

involves several key problems before printing

page content generation: in order to automatically generate pages, an imaging mode that can create, locate and operate basic elements is needed. Apple announced that it intended to replace pict with PDF primitives as the basis of QP in OSX, which eventually led the image workflow to WYSIWYG (what you see is what you get). This new idea points out that page building software needs a comprehensive tool that can PDF files

adobe "K2" (now InDesign) may meet this requirement in the future. At present, a small number of group edition software (such as PageMaker) can support PDF files, but in many schemes, it is still necessary to use EPS format again

pre draft of page content: PDF provides a common format for multi-point collaboration. Its reliability is like fax. It can be browsed by any company on any platform and output to any printer. In order to adapt to high-speed file transmission, images can be sampled or compressed in the network. Some plug-in developers provide more powerful annotation tools, which can freely outline and highlight the elements of the page, and even record supplementary suggestions in the form of audio. Secondly, some issues should be paid attention to in pre typing, such as output font, filling type and color space, etc

digital manuscript: in order to ensure the correct generation of PDF files, the printing and publishing industry needs a standard way to save and apply the predefined structure settings of distillers, which can be published outside the page builder. The printing technology standards committee is developing a standard for digital manuscripts in PDF format, called "pdf/x-1", which adds some extended functions to the description of PDF1.2. It is a general trend to include degradable materials, including trapping, color space, and resource reference of PDF file content. Pdf/x-1 is expected to become a self-contained file that carries all the necessary information for output

pre check: the page content must be valid at both ends of the digital interaction. Pre inspection is to clarify the context of the problem, that is, the relevant design and construction to meet the requirements and industrial standards. As for the work of "distilling" postscript into PDF files, it is to remove the stains in the page content and make it conform to standardization. However, PDF is a very flexible file format, and some incorrect structures and human errors will also muddle through. Therefore, a visual screen proofreading PDF file can capture these error factors. Fortunately, as an open system, PDF makes the automatic parsing and analysis of PDF very easy

transmission: PDF has been used as a first format for a variety of business transactions, which can be accessed through web browser, FTP address, e-mail or a managed network service

prepress: media production must be able to complete the page composition operation, and there is no need to be distracted by irrelevant page elements. Many OPI solutions can replace high-resolution images in PDF archives. Opi2.0 annotations will support the next version of the PDF standard. With some software tools, page elements from the main body of the page can be inserted, and application software supporting dynamic database driven PDF group edition is emerging

Group Edition: the browsable nature of PDF pages makes it easy to pair PDF digital layouts on the screen. Therefore, it is not surprising that more and more postscript group packages have absorbed a certain degree of PDF support. In the predefined template, all pages can be replaced

last minute: printing production needs a stable page format, which can protect the page content from the impact of the processing process. However, media production also needs to be modified at the last minute. In theory, PDF meets these requirements. But this is not the case in practice. The function of PDF file is very limited. For example, it is a big problem to modify the text block to adapt to the change of a word

rip processing: the goal to be achieved in the workflow is that PDF can directly rip and add processing to PDF files. This requires the use of pjtf control instruction list to be combined with Adobe's extreme rip system. The BRISQUE of saiangel can process pdfrip, and the aikefa aipuji workflow has added some pjtf functions, but many PDF workflows turn PDF back to postscript for the final rip processing. Generally speaking, the productivity of PDF's own rip processing is determined by the final output

trapping: PDF does not adopt the scheme of direct trapping, but as a color, vector based file format, PDF is a very useful input file format for the data flow in rip and the technical scheme of trapping after rip

contract proofing: for digital contract proofing, whether it is done locally or remotely, it must be very close to the imaging characteristics of the final print. The new generation of affordable typewriting equipment enables accurate reproduction of colors at all workflow points in the media production cycle. The stability of PDF in the reproduction and transmission of high-resolution color data makes PDF a reliable standard format accepted by a variety of color drafting equipment. Like printing, rip processing of vector page content can be repeated "reprinted", provided that the control and calibration are correct

printing and binding: the traditional simulation processing needs to optimize the combination of processes in a single network environment. In 1999, the organization called "international collaboration on prepress, printing and post press integration" (CIP3) adopted pjtf as the official format of printing production data. This standard will enable a PDF data file to integrate all processes in media production until binding


in printing production, the pregnancy of PDF has ended, and the benefits of its application in all aspects of the printing and publishing industry are real. The gap in the current PDF workflow will always be closed. A large number of innovative development will accelerate the recognition of the market, and the industrial restructuring around PDF will be faster and fiercer in the future

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