Foldable Magnet BoxCTP and Digital Proofing: A tech combo that goes hand-in-hand

Foldable Magnet BoxCTP and Digital Proofing: A tech combo that goes hand-in-hand

Digital proofing, as the name implies, is based on the digital prepress system, in the process of prepress design and production, according to the printing production standards and norms to deal with the page graphic information, the use of digital output system, directly output color proofs, that is, the use of digital manuscript directly output printing proofs. Now the most commonly used digital printing technology, is the use of large color inkjet printer as output equipment, direct output printing color proofs, and as the final printing contract proofs and reprinting basis.

CTP technology is Computer to Plate (Computer to Plate) for short. This technology in a nutshell is to complete the pre-press design of graphic information, through related equipment directly output to the printing material above. Computer direct platemaking technology is a broad category of technology, whether it is lithography (offset), gravure, relief printing or screen printing, there are corresponding computer direct platemaking technology. But in the real printing industry, CTP technology generally refers to the computer directly offset printing plate. The CTP technology mentioned in this article also refers to the computer direct offset printing plate.

Digital proofing and CTP technology are interdependent

Digital proofing and CTP technology are two independently developed technologies, but they are bound to be bound together by common characteristics. Especially, the application and popularization of CTP technology has promoted the development of digital proofing to a large extent. Digital proofing as a technology can exist independently, but CTP technology to want to develop, but must rely on the help of digital proofing. The reason is very simple, CTP technology is the result of the plate, but just look at the plate itself, is unable to know the final printing effect. Because CTP technology eliminates the intermediate medium in the process of plate making - film, so it is impossible to use the film as the traditional plate making process. So how do you know what the final printed product looks like? There is only one method, that is, with the help of digital proofing to complete proofing, sample signing and tracing work. Perhaps some people ask, with CTP platemaking mechanism of the version of the direct prototype proofing can not be? Yes, in theory, but no one is going to do it in terms of cost. Therefore, digital proofing has become an essential assistant and auxiliary technology of CTP technology.

CTP technology + digital proofing + workflow software, together constitute a complete digital prepress plate-making solution.

Digital proofing method

Now the printing industry uses the most digital proofing technology, proofing is very high quality large format color inkjet printer or large format color laser printer for output equipment printing proofs. This kind of equipment is continuous adjustment output equipment, although some manufacturers try to use color inkjet printers to simulate printing points, but the effect is not very ideal.

In addition to the continuous adjustment of digital proofing equipment, some companies have also developed "real point" digital proofing equipment, the most representative devices include Fujifilm's Final proof and Kodak's Approval XP proofing machine. But this kind of specialized equipment is very expensive. So in the actual digital proofing production, or large format inkjet printer such equipment is more common. [next]

The similarities and differences between digital proofing and CTP technology

The similarities between digital proofing and CTP technology are obvious. Digital proofing from the digital file directly output proof, the middle eliminates the film, printing, printing press cumbersome links; And CTP technology from the digital file directly output plate, also omit the film, printing and other links. Whether it is digital proofing or CTP technology, it starts from digital files and reaches the final result directly. What holds the two together is the digital prepress file, which remains the same throughout the process.

But the words are simple, but the actions are far from such an understatement. First of all, although the digital file is the same digital file, the output device is not the same, the output content is not the same. Digital proofing equipment directly output color proofs, the formation of color images; The output of the CTP device is a printing material with a color separation dot. The two color gamut is different, the form is different, the material is different, the imaging principle is different.

In addition, the CTP output plate is still a transition product, but also need to be printed on the machine, can be converted into the final printed matter. The transmission of the image information in the middle is difficult to achieve 100% consistency, therefore, even if the printing plate image information expressed by the color content and digital proof is completely consistent, the final print effect can be fully matched with the color proof of digital proofing, its difficulty is very large. This is also the industry's most headache proofing and printing mismatch problem.

Digital proofing, CTP cooperate with each other to achieve perfect color

Digital proofing is to simulate the printing effect, as the customer sample and printing with the sample standard, so the ideal goal of digital proofing is to be as close to printing as possible. In reality, most high-end color inkjet printing systems use more than 6 colors of ink, its gamut is wider than that of offset printing press, with a wide gamut to simulate a narrow gamut, in principle can be realized. But to get the two gamgames to represent the same color, you need to use color management software to establish a relationship between the two gamgames. The method is to set up the ICCprofile file of each digital prototyping equipment and printing press, as well as the dot compensation curve of the CTP equipment, in order to achieve the matching of the two gamut as much as possible.

In this process, the common practice is to make an offset press ICC characteristics file; Then the ICC file is used as the printing source of the whole system, and the dot compensation curve of CTP output is obtained by comparing and adjusting the printing effect of standard printing proofs and CTP output plates. After the output dot compensation curve of CTP is determined, the printing plate is re-output and the standard proof is re-printed. A spectrophotometer was used to detect the newly generated printing standard proofs, and the obtained data was generated by using color management software to print ICC profiles. Finally, the color and step restoration of digital proof and printed proof are compared, and the color difference between printed and digital samples is measured. After several times of correction, the color selection and cycle correction function of the software are used to achieve the goal of color consistency between the two proofs.

After such adjustment, digital connection can be established directly in digital proofing, CTP equipment and printing press. So that the digital proofing can be more suitable for the actual effect of printing, so that the printing equipment can catch up with the color of digital proofing.

Digital proofing technology was not developed for CTP, but with CTP technology, it is inevitable to use digital proofing. Digital proofing and CTP technology hand in hand, together constitute the key link between pre-press and printing, but also become the only way to the development of digital printing technology. And in the continuous development, these two technologies also continue to promote each other, constantly achieve new transcendence.