Detailed description of PDF to printing (2)

The key to integrating the PDF file format into the high-end prepress environment is that Adobe must develop an architecture that allows it to function normally with large Postscript file processing and printing, and make it accessible to OEM manufacturers. The Extreme system was built. These Extreme systems happen to have the essence of the incentives that printing professionals should know.

The new prepress architecture based on Adobe's core printing technology—Extreme is designed for computer service companies, prepress workshops, and commercial printers. The Extreme-based integrated workflow system automates prepress operations and helps optimize the output of Adobe PDF and PJTF (portable job ticket format). The main advantage that Extreme has is to increase the reliability and consistency of the flow of complex print jobs. It is extremely useful for prepress technicians who have to deal with bad files in the Post-script RIP. Adobe Exterme solutions can also run across multiple CPUs, distribute digital workflows, perform final stage editing, and support multiple raster image processing.

The automatic Extreme Job Ticket Processor is another important time-saving device. These processors collect and execute the special instructions provided by each job ticket, giving prepress technicians the ability to manage, edit, and specify the specific job processing information throughout the print cycle. The job ticket can be used to determine and change the layout, make-up, OPI, and color separation data on a per-page basis up to the final copy. It gives the user the ability to automate print jobs by embedding special instructions in their jobs, and allows customers to add functionality as their requirements change.

InProDuction providing control tools

As for the prepress function under control, Adobe must determine the address of the front end of the PDF file. The answer is to introduce a complete PDF-based print production workflow that enables print designers to produce reliable PDF output on desktop computers.

Adobe Acrobat InProDuction provides the tools necessary to control PDF-based production workflows, including the use of special tools for checking and correcting specific problems in production, managing color separations and color conversions, specifying cutting and bleeding, and determining tight fitting parameters. Preflight tools.

Inproduction also allows users to generate PDF files with folded hands, manage color settings, determine fill-in parameters, convert RGB, Lab and CMYK colors with ICC's color profile file, and preview the separation results on the screen. Designers can also map one color to another, identify, save, and share production parameters to automate the production process, identify sheets, cuts, and bleed boxes to prepare for folded PDF files. Layout boxes can be configured to put PDF items into the design.

Based on Acrobat 4.0 (including the programs used), Inproduction works smoothly with Adobe Photshop, Illustrator, Indesign, Press Ready, Postscript 3, and Extreme, to provide a complete PDF workflow.

Adobe's partners

Adobe’s new innovative design based on PDF technology has produced a new generation of front-end prepress workflow system based on Adobe Extreme and PDF. Early adopters were Prinergy System from HeiDelberg/Creo, Apogee from Agfa, and Brisque Extreme from Scitex.

Further innovation is how an open PDF-based architecture can excite existing partnerships between competing companies. For example, Agfa, Creo, and Heidelberg Printing Machinery have recently announced open system connectivity that enables Apogee and Prinergy workflow management solutions to support Agfa, Creo, and HeiDelberg/Creo imaging engines.

Enfocus Software developed Pitstop Server, a plug-in to analyze PDF features and graphical objects generated using Adobe's new full-page layout program (also based on the PDF structure) and preflight prepress preparation.

Lantana Research Launches Crackerjack PDF Workflow Optimizer, which expands the use of Acrobat and PDF by providing expert control over the printout of image imagesetters, plate imagesetters, auto plotters, digital printers, or other related equipment performance.

More PDF-related products and methods can be obtained or just emerged.

How fast will the PDF take over the digital prepress environment from the printer (PDF direct printing)?

Although the speed of adoption of PDF is not entirely exponential, it has indeed grown steadily. We have installed more than 100 Prinergy systems. In the fall of 1999, our first batch of sites started using 100% PDF workflows. Although it is still in its infancy, we have indeed crossed the most difficult period.

Because so many prepress system vendors have produced PDF-based systems, it can be said that by the end of 2001, you will see 50% of commercial printers using PDFs to press the workflow.

Just as with any other industry sector, the pre-press development is a shift from analog to digital. If we can reduce the period of prepress operations to two or three days, or in the extreme, to two or three hours, we can think that using PDF is achievable, so that the printing industry will have a good opportunity to maintain excellence. Competitive advantage over other digital communications media such as the Web.

1. Features of PDF PDF features are summarized as follows:
Transmissibility. The PDF file supports 7-bit Ascii code and binary encoding, which can be correctly transmitted in various network environments.
Platform independence. PDF files have both hardware and software platform independence. The format and content of the PDF files that the user sees in different environments (such as different language operating systems and different hardware platforms) are exactly the same as when the author was created. This feature is very suitable for information exchange, eliminating the trouble of garbled code.
Font independence. The PDF file can have its own font or font description information, and it can still display correctly if the user's system lacks the required font.
Supports multiple compression and encoding methods, and the files are more compact. Compression, encoding methods are: Asciihex, scii85, lzw, runLength, ccitt group3, ccitt group 4, jpeg, flate.
Supports interactive operations. May contain interactive forms and hyperlinks. Support sound, animation.
Supports random access to pages.
Supports the continuous addition of modifications to facilitate minor modifications and improve efficiency.
Security control. Supports various levels of security, such as reading only, not printing and selecting text, being readable, printable, but not modifiable, readable, printable, modifiable, etc. This kind of security control is very important to protect the copyright of electronic publications.

2 PDF Structure 2.1 PDF File Structure The PDF file structure (ie, the physical structure) consists of four parts: file header, file body, cross-reference table, and file end. See Figure 1.
The header indicates the version number of the PDF specification that the file complies with. It appears in the first line of the PDF file. Such as %PDF-1.2 indicates that the file format conforms to the PDF 1.2 specification.
The file body consists of a series of indirectobj objects. These indirect objects constitute the specific content of the PDF file such as fonts, pages, images, and so on.
The cross-reference table is an indirect object address index table set up to allow random access to indirect objects.
The end of the file declares the address of the cross-reference table, indicates the root object (catalong) of the file body, and also stores security information such as encryption.
Based on the information provided at the end of the file, the PDF application can find the cross-reference table and the root object of the entire PDF file, thus controlling the entire PDF file.

Source: "Guangdong Printing"