This article is the first in a series of articles published in the magazine "Flexo & Gravure International". Here, the author tries to explain common terminology in some modern printing technology environments. These terms often make beginners in the printing industry feel vague. Of course, for those who are interested in this field, the explanation of these basic terms and terms is sufficiently detailed. The purpose of this is to facilitate communication with each other without misunderstanding.
The prepress system refers to all the components of a modern printing company that are prepared for the needs of printing. In addition to equipment operators, the protagonists of the prepress system are computers and other electronic devices. In a flexographic prepress system, most work programs are executed in a variety of computer systems. Thus the focus of this series of articles is on these computer systems. The Origin of Digital Prepress Systems First, let's review history: In the 1970s and 1980s, the widespread use of digital color separations made electronic image processing possible. The first-generation image acquisition instrument (discussed in detail later) is a method of optically scanning an image manuscript (typically a transmissive document), and the document information is immediately recorded by exposure to create a film-making film. The resulting color separation films are also synthesized using conventional methods (such as film split exposure) to produce a complete page.
Image information can be transferred to the hard disk of the computer in the form of files instead of the appearance time of the color separation machine exposed on the film. This is the beginning of the era of the traditional color electronic prepress system (CEPS). Using the CEPS system provided by Hell, Scitex, Crosfield, or Dainippon Screen, the images can be viewed and processed on a computer screen and processed. Full page imposition. In fact, the electronic working process has remained unchanged since then. Of course, the computer system used today has undergone great changes from the beginning.
At that time, the CEPS system was very expensive, but soon the manufacturers of such systems were all disappeared from the market. Even the term "CEPS" was not found in the terminology of modern platemaking technology.
What ultimately destined to the fate of the traditional CEPS system? In addition to its expensive price, it is their closed architecture. If a user chooses a certain system, he or she will actually use a series of products provided by the system for a lifetime because the computer of that system can only run the programs developed by that manufacturer, and the system upgrade service only Can be provided by the manufacturer. In this way, there are more or less incompatible places among various systems. In the next section we will return to this issue to discuss.
As we have seen today, the revolution in prepress technology quickly ended the era of traditional CEPS systems, with only a few of them preserved. In some packaging and platemaking companies, the traditional CEPS system will always be replaced because it cannot take into account the need for special colors. In fact, these "dinosaurs" are now extinct.
Subsequently, Apple's Macintosh began to dominate the prepress process area. It was not even clear at first that the Macintosh was specifically designed as an image editing workstation. Its excellent graphical user interface made it a popular working platform for the desktop publishing system (DTP). DTP provides a relatively easy-to-use program that eliminates the need for creative skills; DTP almost replaces the functionality of traditional typesetting machines. Since then, the typesetting work has basically been performed on DTP workstations. When everyone suddenly discovers that they are in a position where they can move "expensive" typesetting devices or even copy studios to their own homes (we will talk about this topic later in the discussion), we can generate them ourselves. In the layout, it was found that the early DTP design quality was a bit flawed because of the lack of technical knowledge of the operators. This situation has changed at the same time, and now there are people who are more capable of this task to operate the system. People began to look for the best designs and tried to rely on professional designers again. They also use DTP workstations, but the responsibilities of the operators are completely different. DTP replaces CEPS
At first, there were some text imposition features and simpler layouts in DTP, and there was no image-based content. However, due to the rapid development of DTP computers and DTP programs, it soon became possible to process image data with high quality.
Although in terms of processing speed, today's DTP workstations have limitations, DTP workstations based on Apple Macintosh computers can generally replace traditional CEPS systems in all performance ranges, just like the original image processing workstations.
It is the installation of the image processing workstation that has caused a fatal blow to the traditional CEPS system. Users no longer need to invest hundreds of thousands of dollars, but only tens of thousands of employees are enough. As a result, DTP workstations began to develop everywhere, and the days of those companies that still sell expensive traditional CEPS systems are difficult. If a company does not recognize the development trend, it can only be eliminated by the market. Prepress system - open or closed?
The emergence of the Apple Macintosh announced the opening of an era of open prepress systems. In the following sections, I will discuss this issue in detail. What is an open prepress system? Is the computer's panel open? Or maybe it is a drum scanner opening operation? Or is it suggestive that the system has defects that are visible to the naked eye?
No, of course not. An open prepress system means that components from different suppliers can be assembled and can be run as a complete system. For example, an operator may have a system such as a computer provided by A, a running program provided by B, C, and D, a drum image scanner provided by E, and a final laser imagesetter (film exposure section) provided by G. This is the meaning of openness.
In practice, prepress workstations usually use Apple Macintosh computers. Now we also use PCs based on the Windows operating system or SUN and SGI workstations for image design processing. The software that assists image processing and typesetting is mainly Photoshop, Illustrator software (both Adobe), FreeHand software (Macromedia) and Xpress software (Quark), Windows-based PC also uses Corel Draw software (Corel). Examples of rollers or flatbed scanners and laser imagesetters can also be cited. Although not within the scope of this article, they should not be overlooked in terms of openness.
So what is a closed prepress system? The old CEPS system is closed. As mentioned above, this is where it is deadly. The closed system is only compatible with specific components, especially the original components of the manufacturer. In other words, once you select an image processing workstation from a specific supplier, all input and output devices (scanners and laser imagesetters) must also be provided by the same supplier. System extensions developed by different vendors are incompatible. The manufacturer originally selected by the user actually occupies a monopoly position.
Fortunately, the era of closed prepress systems has become a thing of the past. Today, every plate-making company can successfully customize a prepress system, which is composed of components selected from multiple suppliers in the market. In other words, this system structure is the best in terms of quality, operation, work structure, operation qualification, and even price. For example, if all the images that need to be processed are corporate mark images and simple line images, high-end roller scanners can be dispensed with and can be performed from a large number of different types of platform scanners or small-format drum scanners. select. Interface - a key factor In fact, in an open or closed system, the important key factor in determining the applicability of system components is not the number of devices but the interface to other devices. Simply put, an interface is a connection point between two system components. As an example, if the color separation scanner is connected to an Apple Macintosh workstation, the interface between the two must be coordinated. The proper cable connection is just one of various factors. The main reason is that the two devices must have the correct connection protocol and they can understand each other. This is a successful connection.
In this connection, the computer industry, not the printing industry, has established many important and open standards, such as the interface specification (TWAIN) of the image input device (scanner) and the postscript of the output device. If the content of a system supports the usual interface standards, the suitability of matching is an important guarantee for incorporating an open prepress system. Disadvantages can be described in an informal way to describe an open prepress system: it is a system that allows users to gather the necessary components at their own discretion. The superiority of it has been fully described above. However, in practice, freedom always involves responsibility. If there are components from different suppliers in a system, then no one supplier is responsible for the quality of the entire system. Ultimately, the user can ensure that the workflow is smooth and efficient. One of the new technologies that emerged with the open prepress system is the color management classification system. This term is the object of discussion in many current technical prepress publications, and is completely unknown in the era of traditional CEPS systems. Since the entire system is purchased from a single channel, it is the supplier's responsibility to ensure that the monitor accurately displays the image input by the scanner and accurately records it on the image output portion. If all the equipment in a factory is derived from a single supplier, unified calibration will be relatively easy.
In an open prepress system, there are various possible combinations of the components provided by different suppliers, and this will bring us back to who is responsible. Because there is no single component producer responsible for the entire workflow (after all, laser imagesetters have their own characteristics, this is not a scanner supplier's problem), the responsibility goes to the user. This is the reason for the rise of color management systems. In terms of color, this additional software platform will ensure that the workflow is predictable in the future. This topic will be discussed in detail in the following series of articles. (to be continued)
Learn about the flexographic electronic prepress technology - introduction for beginners (Part 1)