PDF development in printing

Since Adobe introduced the version of Acrobat 4.0 and Portable Docuemnt Format 1.3 in 1999, PDF has established a new world in the printing and publishing industry, truly becoming an exchange file format for many prepress and printing processes. .

More than 500 kinds of products can be accepted in PDF format. If you look over the Internet, you will find many types of software tools that can be used to generate, manage and edit PDF files in the print production process. PDF is gradually becoming a printing process. The standard format is now.

However, just as electronic prepress operations have just started to develop, there are still some problems with the use of PDF in printing. How many high-quality prints are printed in PDF format? What are the differences between PDF files and application-originated files in print production? PDFs really match the industry's compression, consolidation, cross-platform, real-time Is the printable requirement? If the PDF still can not solve these problems, but in the pre-press, printing problems, which in the end to take it to do? PDF vision of the printing industry in the end, and the user of the PDF Where are the expectations?

● Print PDF

The above problems lingered in the minds of many industry observers or analysts. In 2002, GATF and Seybold Publications did a statistical report on the status of PDF applications in the industry. Their findings were based on the analysis of PDF usage in the printing process. Problems encountered in questionnaire surveys and PDF processes, and the result of exporting a variety of applications to a PDF file and output through various PDF tools.

The GATF Press report "PDF Century: PDF Usage in the Real World" opened a new horizon with a questionnaire of 21 questions. The GATF obtained 85 effective from the prepress, the full-time manager of the printing company or the technical manager. Questionnaire. When asked "What is the ratio of using files in different formats?", QuarkXPress accounted for 53%, and PDF accounted for about 23%. The rest was PS/EPS or other native format files. The investigators also reflected the major advantages and disadvantages of PDF.

The five major benefits of using PDF in the survey are: fewer problems across platforms, smaller files, faster system processing, soft proofing and easy previewing. On the contrary, 88% of respondents stated that the biggest problem with using PDF is because the customer did not fix the file, or even completely forgot that the printing industry had reminded them to pay attention. The most common problems with PDFs from customers are that the fonts are not embedded, the resolution of the graphics file is too low, no blood is made, or the wrong color space is used.

The Seybold Report expanded the scope of the survey from the GATF questionnaire and collected 2,221 valid questionnaires. The sources included those who were primarily responsible for producing PDF files and providing services in prepress and printing with PDF files. The use of PDF in the PDF Workflow Shootout and Usage Survey in the Seybold Report is higher than the GATF survey. Of these, 33% of filers and 40% of filers think that QuarkXPress is their most common format, while 30% of filers and 29% of filers think PDF is their first choice. The alternatives are files of other formats.

When asked what the first three advantages of using PDF are, the answers to the questions are cross-platform issues, fewer processes, more efficient processes, and smaller files. Conversely, the three most important issues in using PDFs are that fonts are not embedded, the image resolution is too low, and wrong color spaces are used. People who make PDF files sometimes find that PDFs and native files sometimes differ.

Therefore, although there are many benefits to using the PDF process, a certain percentage of people or technologies will still encounter some problems before the digital printing, and smart PDF tools are needed to help manage it. The common problems are as follows:

1. Fonts use special TrueType words or OpenType words that indicate "not embeddable."

2. Problematic bitmap files, including DCS, Duotone Special Color, TIFF, JPEG...

3. The reference line of the vector diagram, the font transfer frame, is imported into the EPS or PDF nest structure.

4. Color management problems, wrong ICC Profile or wrong usage.

5. Separation problems, special color name designation errors, misuse of four-color black, or use of RGB mode.

6. Direct pressure and superimposition, for example using the transparency function of PDF 1.4, but the prepress/printing system is not updated synchronously.

7. Page settings, such as cross-page, bleeding and border settings.

This statistics and other data from the two reports shows that the use of PDF is increasing. Although PDF can improve the prepress and print production processes, the PDF process is also plagued by various problems just like the beginning of the digital process. What is the solution to the problem?

● PDF tools

The problems with the PDF file originated from the use of the original application at the design stage. This happened when the file was created, and the ratio was higher than when the PDF was generated. That is to say, all content in the design process must follow all the basic specifications for making a complete file. At this stage, preflight software can be used to check the content of the file.

In the PDF generation phase, it should be noted whether Acrobat has been properly installed, whether the Postscript printer driver has the latest version installed, and whether Distiller has the appropriate settings. A simple user usually does not know that Distiller has four standard settings for screen, e-book, printer, and printing. If you use the standard setting, be sure to select the settings for printing. In many processes, using only the default print settings is not enough. You need to make additional manual settings to make the resulting PDF file. High quality prints. These settings include the version of the generated PDF file format (1.2, 1.3, or 1.5), the compression of images and text, embedded color management messages, and even job ticket information, OPI, or direct pressure settings.

In Acrobat 6.0 there are some new features that assist in the generation and management of PDF files for printing, because the PDF files for printing are too complicated for the average person to produce and manage, so some units developed like CGATS, ANSI and ISO. PDF/X-1, PDF/X-1a, and PDF/X-3 standards are designed for prepress or print formats. Acrobat's plug-in programs also support PDF/X compatible files. Software partners have also designed suitable software for the various processes of PDF.

Standard Acrobat is the most common and used software in PDF generation

● PDF/X standard

　　 PDF/X is correctly said to be a limited subset of PDF, developed by CGATS, ANSI, and ISO. It was originally designed to enable the correct exchange of printed digital data, especially the advertising flow in publications, PDF/X. Defined as a reliable, no special technical discussion or involvement. PDF/X defines a set of required, prohibited, restricted, and suggested conditions for PDF. The related PDF/X distinguishes several different definitions.

PDF/X-1:2001 and PDF/X-1a:2001 (ISO 15930-1:2001) are used in the printing production process. The difference between the two is that the latter prohibits the use of encryption and OPI objects. There is no difference between the two. In PDF/X-1 or 1a files, all fonts must be embeddable and embedded. The image part must be CMYK, DeviceGray, DeviceN, or special color. RGB or Lab color mode cannot be used. Trapping settings can only be set to on or off.

PDF/X-3:2002 (ISO 15930-3:2002) is similar to PDF/X-1 except that it allows the use of device-independent color spaces such as RGB or Lab, and it appears to be the case for processes that require simultaneous use of different color spaces. It is very important, either for the output of the camera or with the ICC profile for color management for other outputs.

PDF/X-2 (ISO 15930-2:2002) CGATS is still under development, but in the middle of last year there was an unfinished document describing its international specifications (not yet an international standard), PDF/X-2 will It mainly serves as data and information exchange between the file provider and the receiver. When approved, it will become part of the PDF/X-3 collection and will also allow the use of device-independent color spaces.

● JDF standard

JDF is a file format based on XML language. It is a specification of the work order in the production process of the industry. It contains the standard of message description and the protocol of message exchange. JDF was originally formed by the alliance of four companies: Adobe, Agfa, Heidelberg and MAN Roland. The purpose was to integrate the management and process information originally belonged to MIS and try to integrate it with CIP3.