Talking about CTP Screening Technology

Undoubtedly, every printing company thinks that the computer-to-plate system can greatly improve the printing quality. Because it does not need to use film, it directly forms images on the plate, which can make the printing shop more tidy and at the same time Let people use more precise dots, reducing the limitations of the four-color printing press. In addition, the computer-to-plate system can reduce dot distortion and maximize compensation for dot gain on the press. In this development trend, many manufacturers have introduced random screening products for computer-to-plate systems.

The traditional halftone screening is what we often call AM screening. It is composed of a series of regularly arranged dots, and the difference in highlights or shadows is reflected by the change in dot size. AM screening has a strong predictability, and the effect on the printing press is better than random screening. The limitation of this technology is that the printer must ensure that the image does not lose dots in the brightest and darkest areas. As the number of screens increases, it becomes more and more difficult to control the gaps between the highlights and maintain the darkness of the screen.

FM screening or random screening uses a completely different approach than AM screening. They can maintain the same dot size but change the distance between dots. Since the dots are very small and very tightly arranged in many areas, the FM screening can reproduce more details (middle tone) while reducing the chance of "Moir" stripes appearing. Images printed using FM screening techniques can often achieve the quality of continuous photo adjustment. However, since FM screening uses very small dots, the problem of high-light dots that often appear in the AM screening process also appears in most of the modulation tones of FM screening. Prior to the advent of computer-to-plate technology, it was difficult to transfer micro-dots from film to plates. Now, this problem can be easily solved.

Many emerging screening technologies are a mixture of AM and FM screening. Hybrid Screening uses the traditional banner screening method in most tone areas, and FM screening techniques in highlights and shadows. By mixing screens, the offset printing plant can increase the number of screens in the AM screening area without incurring additional burden on the press. The following are some of the most popular screening products currently on the market (Agfa, Artwork Systems, Esko, Fujifilm, Heidelberg, Kodak, Rampage Systems, RIPit, and Screens).

Agfa

Agfa claims that its own screening technology will combine the advantages of AM and FM screening. The company's: Sublima is a patented product that integrates two technologies into one solution. It is also the first Agfa solution to use XM's patented technology. In the development process of Sublima, two Agfa technologies were used: ABS (Agfa Balanced Screening) and CristalRaster FM screening technology.

Let's look at the following: How Sublima works. In the midtone zone, Sublima uses ABS technology for clear and accurate reproduction. In the more troublesome highlights and dark areas, Sublima uses FM technology to reproduce the details of the image. However, this software cannot be easily converted from one technology to another. It uses patented technology to determine the switching points between the two screening technologies and enables a smooth transition without affecting the image's performance. Although the FM screening area uses a relatively small network, they will still be ranked according to the screening angle established by ABS. The net result is a completely new network. : Sublima can reach 210, 240, 280 and 340 lpi screens respectively.

Sublima software takes into account all the variables. It can calculate the minimum dot size that the printing plate can print on each type of printing machine, thus allowing the printing worker to make adjustments on the printing machine - this is a place that it is stronger than the frequency modulation screening.

Sublima's built-in calibration curve automatically compensates for different dot gains. It can keep 1% to 99% of the dots in the long print without losing it. The biggest advantage of this technology is reflected in prepress and printing. At the highest screen number - it can only perform RIP at 2400dpi resolution. The printing effect of 340 lpi does not differ from that of 150-lpi - it also includes ink balance and plate properties.

Artwork Systems

Artwork Systems is the industry's leading provider of professional prepress software that has developed Concentric Screening technology. According to the company, Concentric Screening is a revolutionary halftone screening technology that divides traditional circular dots into finer concentric rings. These concentric rings reduce the thickness of the ink film on the plate, giving users greater print stability and color saturation. Concentric Screening is the first halftone dot that uses a different internal shape and is also the world's first "non-stereoscopic" halftone dot. Artwork's production printers can increase the number of screens, even double the number of screens, without worrying about spots, dot gains, and other problems caused by the number of high-line screens.

Concentric Screening has all the advantages of the second-generation FM screening technology. It is print-friendly, easy to use, and can achieve the smoothness achieved by conventional AM screening. In addition, it can also be used in the Nexus and Odystar workflows introduced by Artwork Systems.

Esko

In September 2006, Esko introduced the new PerfectHighlights flexographic screening technology. It brings new tools to Esko users, carton makers and label printers, enabling them to know how to achieve the best results in the screen printing process and plate making process. Printers can set optimal screening parameters for specific printing environments, inks, substrates, and printing presses, thereby increasing the value that package buyers can gain, while also providing them with a greater competitive advantage. PerfectHighlights can print 1% to 2% highlights in a variety of ways. It works with Esko's other screening technologies to provide users with the best midtones and shadowing effects.

In addition, Esko has also developed a variety of screening technologies including Samba Flex and Groovy Screens. Both SambaFlex and Groovy Screens are hybrid screening technologies that use amplitude-modulated dots in most areas of the image and use frequency-tone dots in highlights and shadows to increase color saturation and stereoscopic effects. Esko also owns HighLine AM screening technology, which can produce very high screen numbers at lower output resolutions. For example: Can produce 423 lpi outlets at a resolution of 2400 dpi.

Fujifilm

Fujifilm also has two advanced screening technologies, Co-Res AM Screening (for normal resolution images) and Taffeta FM Screening, which was launched at drupa 2004.

Co-Res Screening is a revolutionary high-precision screening software developed by Fuji Film Corporation that enables customers to print high-line images with standard output resolution. In this way, users can increase the productivity of high-line screening, and at the same time obtain more detailed reproduction effects in highlight areas.

Fujifilm also developed Taffeta's FM screening software, which allows CTP users to print more detailed, higher-quality products. Taffeta combines Image Intelligence, a fully-featured digital imaging technology specially designed by FUJIFILM, to help printers solve problems that often occur during the FM screening process, and can effectively increase the range and accuracy of color reproduction, and reduce the “Moir” fringe. The production. The new Taffeta FM Screening also uses a particle optimization algorithm that uses optical characteristics to simulate the printing effect and uses dot shape optimization algorithms to reduce the graininess of the image and improve the printability of the printing plate.

Fujitsu claims that Taffeta has the following features:

Completely eliminates "Moir" stripes and rose spots Increases the saturation of basic and inter-colors Better reproduction of image details Improves texture and printability of printing plates Eliminates unevenness and graininess of printing plates