PDF cross-media publishing features

Postscript is designed to be printed and published as a de facto industry standard for digital prepress technology: Multimedia applications have been developed to a very high degree when designing PDF documents, so it is suitable for print publishing and electronic publishing: after the emergence of web publishing , PDF still found its place.

The PDF has features that meet the requirements of cross-media publishing because it is rooted in Post script technology, inheriting all the advantages of the technology, and taking into account the needs and technical characteristics of electronic publishing. In addition, the display Post script technology is also integrated in the PDF in order to obtain the consistency of the hard copy output and the screen display effect.

After cross-media publishing requirements have been designed and produced, the results of the work can be used for a variety of publishing purposes, namely one production and multiple uses. Cross-media publishing also requires that the production content has an adaptive processing feature that is consistent with the purpose of the publication, that is, the relevant parameters can be set for a specific publication purpose to suit the recording technology and media used by the publication.

First, cross-media publishing and its basic requirements

The basic tasks of cross-media publishing can be summarized as

"The processing, use, and storage of data files can adapt to any kind of output," and this basic task can also be used as a definition of the concept of cross-media.

From the definition of cross-media, we can see that it not only sums up and summarizes the relationship and technical characteristics of digital prepress and digital printing, but also reflects the new requirements put forward by the ever-developing social needs for print publishing and electronic publishing: It also expresses the broad applicability of this concept, that is, the cross-media concept is the basic requirement for the cross-use of traditional publishing, electronic publishing and web publishing content. Cross-media publishing requires user-designed content to have certain basic characteristics.

1. Content adaptive processing features

After the content is produced, it needs to be finished. With the advent of electronic publishing systems, the professional knowledge requirements of operators have been reduced, and more and more people are engaged in the production of publications. However, there are misunderstandings on the fundamental issue of significant differences between production and finalization. Design and production are only the preliminary work for the completion of the dissemination of content, during which it may not be necessary to take into account the use of the content and the recording medium, but it is therefore not appropriate to ignore the importance of the final draft. After the design and production are completed, it should be targeted at a specific dissemination method and according to the recording technology and recording medium to be used for targeted processing. This process is called finalization. After the concept of cross-media is proposed, the final draft becomes more important.

Taking the production content for a print job as an example, the page should have adaptive processing features for recording information using a combination of paper, ink, printing press, and a specific printing process after being processed. For example, the current page should be converted to CMYK in other color spaces

The color space (this process is also called color separation in the digital pre-press process) compensates the page content for printing presses and printing plates that are not accurate enough to generate overprints. The quality requirements and copying of printed materials are required. It is required to select different screening parameters and add bite marks, cutting marks, and signal strips on relevant pages to facilitate printing plate installation, cutting, and control of printing quality.

2. modify

Everything in the world is in development and changes, and customer requirements may change. In addition, the design and production of good content can not be without errors, such as text input errors, graphical expression errors. For this reason, cross-media publishing requires that the produced content be edited and corrected before output to reduce losses and create favorable conditions for cross-media publishing.

3. Data format conversion

With respect to the publication content production process that uses digital devices and digital technologies in its entirety, there are different requirements for digital file formats for publishing methods, depending on the nature of the recording media and the mode of dissemination. Therefore, after the content is produced, the data format conversion should be performed as needed. For example, the documents used for printing and publishing are converted into Post script, EPS or PDF formats, and the documents used for network publishing are converted into HTML formats.

Judging from the above-mentioned basic requirements for cross-media, effective implementation of cross-media is not enough due to traditional output technologies. It calls for new output technologies, such as Adobe's Post script.

Level 3 and PDF technology based on successful development SUPRA structure.

Second, PDF is suitable for printing and publishing features

The characteristics of PDF for printing and publishing are mainly divided into two aspects: first, it continues to support prepress and printing workflows, and second, each PDF description page is independent of each other.

1. The importance of page independence

Physically, a Poot script file describes pages that are connected to each other. They are arranged in the order of the contents of the publication. After being output on a hard copy device, a sequence of consecutive pages is obtained. These pages have a sequential relationship, a logical relationship, or a causal relationship. . In the file structure, each Post script file is actually a collection of Post script instructions, divided into two parts: object definition and description. The description is about the object description. Because of this, it is possible to generate objects and objects. The relevance of the object and the object leads to the relevance of the page because the related object may be in a different physical page.

The biggest drawback of page correlation is that it is very error-prone when outputting. For example, when RIP interprets an object on page 5, it finds that it is related to the object on page 2, then RIP will jump to the 2nd page. Page, reinterpret the object, and return to page 5. If we only need to re-interpret it once, the problem is not big. It is a waste of time. The problem is that a related object may be interpreted again after being reinterpreted, so that the result of repeated interpretation is the multiple nesting of the interpretation, which results in the output of the Post Script interpreter issuing a limit error message or an overflow error.

The fundamental difference between PDF and Post script is that RDF is a document format, not a page description language. Although it also describes objects, because there is no programming structure, pages and pages are not related. Therefore, after the application Acrobat Distiller, which generates the PDF file, "distills", the relevance of the page to the page is cut off. From this it can be seen that the page-independent nature of PDF enables it to meet the basic functions of cross-media publishing and can be used for print publishing, electronic publishing or web publishing without additional processing.

2. PDF print publishing function

Since PDF is based on Post script technology, there should be no doubt that it should be published in print. However, the PDF format provided only a limited degree of print publishing capabilities in the early stages of launch until

The Acrobat 3.0 version became quite perfect when it was introduced. Considering that there have been many articles on the printing and publishing function of PDF, there is no intention to discuss it in more space here. To put it together, PDF's support for print publishing manifests itself in:

(1) PDF, like the Post script, uses objects similar to the printing process (template coloring) to generate objects. This is the most fundamental attribute of PDF:

(2) Beginning with version 1.2, PDF starts to support the CMYK color space, which is necessary for the realization of print reproduction:

(3) Each Post script file or EPS file is always associated with the page, which is in PS or

EPS file-based workflows often produce the main reasons for limit checking errors or overflow errors, but when PS files or EPS files are converted into PDF files, the relevance of the pages is cut off, ensuring that each PDF page can be output stably. :