Comparison of workflow solutions

In all prepress solutions, whether it is CTF (computer to film), CTP (computer to plate), or CTPrint (computer to print), digital data exchange is a common feature of them. The heyday of film as a form of data exchange has passed. How to deal with "digital data" has become a core issue in the work process. Digital data processing is a very promising topic and many solutions have been introduced. The Ipex 2002 exhibition will provide an excellent opportunity to showcase a variety of different types of solutions.

Here we can compare four solutions based on Postscript-based workflows, dedicated workflows, bitmaps, and PDF workflows. In fact, each solution has its advantages and disadvantages.

Postscript workflow

Postscript data in the Postscript workflow is either generated by the customer or converted by the EPS file or generated by an open application software file. The advantage of the Postscript workflow is its openness and independence from the manufacturer. The disadvantage is that production reliability is reduced due to the presence of a non-single Postscript page description language. There are potential pitfalls in many aspects of the workflow, such as missing words, incorrect image resolution, accidentally generated decorative colors, wrong cutting data, and more. Furthermore, the correct syntax of the Postscript language for this type of workflow is also very stringent because of the incorrect code in the case of a RIP that is not tolerated. Can cause bitmap generation errors.

Inside the print production department, operators can find some unique features that can be identified and corrected by themselves when encountering errors, and Postscript data files can be used to optimize the correction function through pre-checking procedures. Using a customer-provided Postscript data file is troublesome. Postscript data file verification and error correction are extremely important. In some cases, the Postscript data file itself may have to be regenerated.

Dedicated workflow

There are two different ways of working with a dedicated workflow. One is to convert a digital version of a customer's group of good, compressed, and large-format versions into a printing house's own format, which can generate and eventually output large-format films, plates, or proofs. The advantage of this method is that it has a higher production reliability provided by an integrated system. This integrated system coordinates the processes in the workflow. The disadvantage is that this dedicated workflow system is incompatible with other systems. Depends on individual vendors and the system is expensive.

The other is to convert a single page into a printer-specific format, with the imposition workstation, RIP, and output device still working in a proprietary format. This approach also has an integrated system with a high level of production reliability. In addition, the ability to predict production time and provide last-minute changes is also an advantage of this approach. The disadvantages of this approach are also the high price of the system, its dependence on the manufacturer's technological improvements, its incompatibility with other solutions, and its lack of support for open standards.

Nevertheless, some vendors are still trying to introduce another solution to replace the manufacturer's own data format with TIFF, TIFF / T format, that is to try to achieve data exchange between dedicated systems. Of course, the prerequisite is that manufacturers can provide direct support for TIFF/IT formats without having to convert the data back to their own format.

Bitmap workflow

Actually, before the Postscript data file is generated, the bitmap workflow and the Postscript workflow have the same features: a single page that has been generated or transferred is converted into bitmap screening data through Postscript RIP and then output. Proof or proof imaging directly on the plate. In the bitmap workflow, only changed or corrected pages need to be re-screened. The advantage of this workflow is that it can separate RIP processing from plate exposure, with the disadvantage of high system prices and dependence on manufacturers. In addition, the write process and the transfer of large data bitmap files are time consuming and the bits themselves are related to the device.

PDF workflow

PDF workflows based on PDF file formats are relatively new. Postscript data or other data formats are converted to PDF format in the Postscript workflow to replace the manufacturer's own data format. The PDF file format was originally developed for the office market, and the PDF workflow has not been effectively used in the printing and publishing industry until PDF 1.3. At the Seybold Symposium in Boston in 1999, Adobe introduced Acrobat 4, making it possible for PDF workflows to meet the requirements of prepress workflows. In addition to technically providing the necessary improvements, PDF workflows are also advanced in that print publishers can provide settings for their customers, who can use these settings to generate PDF files. At the same time, vendors have provided some solutions to automate this process and can also control them. Initial solutions include Agogee Creat from Agfa and Synapse from Creoscitex.

Postscript data also appears at the beginning of the PDF workflow, but PDF avoids the unpredictability of the previously mentioned Postscript page description language. Postscript files from any application or any platform can be converted to PDF in Acrobat Distiller. The non-unitary nature of Postscript can hardly guarantee the reliability of production, and PDF is very reliable in this respect. Furthermore, PDF is device-independent and has a high compression algorithm capability, guaranteeing a flexible and compact data format.

There are also two ways. One can be configured by the user as a PDF workflow system. That is, the user selects corresponding programs from different suppliers in PDF generation, pre-check, trapping, layout, and output. Assemble your own PDF workflow. Alternatively, if not closed, the solution can be configured and coordinated at least logically according to a technical route. Currently, this workflow solution includes Apogee of Agfa, Prinergy of Heidelberg and Creoscitex.

The advantages of the PDF workflow are the compressed file format, the predictability of the processing time on the RIP, and the independence of manufacturer's features. The disadvantage is that not all PDFs are suitable for printouts. In fact, the editability of PDF has only a small part of the imposition for imposition. Despite this, the new PDF 1.4 retains the PDF structure and, with the application of the PDF workflow, its development speed has been considerably improved. Using Acrobat's soft plug-in architecture, the new solution enables some functions, such as PDF assembly, multi-language PDF documents, color separation, trapping, image and graphics correction, to be added to the PDF workflow more quickly without having to Rely on any manufacturer.

New JDF

As Swiss PDF expert Stephan Jaeggi points out, for all workflow systems, even if only one parameter is changed, it is necessary to regenerate all pre-defined workflows. Simply put, the number of "hot folders" will be doubled by the appearance of a new parameter. The solution to this problem is emerging, and for the PDF workflow, it is only a bit slower. One solution now known is to use the Job Definition Format (JDF). The first edition of the JDF was adopted at the Boston Seybold 2001 conference recently held by the CIP4 committee (CIP4 members include major manufacturers such as Agfa, MAN Roland, and Heidelberg). All the important parameters on it are valid for PDF documents in a format that can be recognized by all workflow solutions, so it will be one of the most promising workflow solutions that will provide cross-system PDF workflows. . People can see many workflow products based on this format at IPex 2002 in Birmingham, UK in April next year.