Networking Technology Advantages and Solutions

As we all know, the printing industry says that AM and FM are not as simple as radio wavelengths. Here are the latest developments in this area.

In today's complex, fully automated prepress workflow, the hot topics of discussion are focused on issues such as PDF, JDF, XML, CMS, and ICC. Screening is no longer the technology most concerned by prepress specialists.

However, recent developments indicate that Canada and other forms of outlets are still the most concerned issues for prepress workflow and output system manufacturers and distributors.

Important production tools

The benefits of optimized screening technology are to bring more vivid prints, clearer details, no moire and process stability to the printing companies, and companies that ignore this technology have missed a very important production control tool. .

Let us first review the development of digital screening technology. It evolved slowly from the process of glass and contact screen screening used in the formation of simulated dots. From the early days of offset printing technology, printing process experts have been experimenting with dot shapes, angles, and screens, hoping to optimize the effectiveness of printed matter and control the process. Digital screening has provided us with a possible method of physically forming outlets so that process constraints are no longer a problem.

When DTP appeared, the early PostscriptRIP could achieve four-color and multi-color digital screening, but the quality was lower than that of analog screening and dedicated high-end color systems. Experienced prepress operators may still remember the extensive and intense discussion of "screening" in the late 1980s.

Later on, there has been a revolutionary change in the configuration of optimized networks, offering more screening angle options than PostscriptLevel1. At the same time, prepress equipment manufacturers are paying attention to PostscriptRIP and applying their rich screening knowledge to desktop publishing systems.

The real revolution is the use of FM or random screening, although it is not a new idea. In the 1980s, it had been used in digital printing processes where the quality of dots was not high. Instead of simulating different continuous tones with different sizes of dots, it was reproduced with the same size and relatively small dot spacing. Tonal adjustment.

FM random screening was just launched at the height of the war on the Internet and was heavily advertised and given too much hope. Since then, the traditional screening method was named AM screening to separate it from FM screening applications.

Clearer effect

Compared with AM, the advantage of FM is a clearer effect, because the tiny dots can produce more hue; ensuring no moire between colors and patterns, making the printing process more stable. However, many obstacles were encountered before FM screening was applied to a wider range of non-special purpose applications.

The unfavorable conditions faced in the early 1990s are: it is very difficult to handle in the CtF environment, there is no exposure range of the printing plate; particle patterns are generated in the gray midtone and peace net area, and it is difficult to adopt ink in the printing machine. The thickness variation method compensates for the color difference. Early adopters of this method seldom persisted.

However, in the past decade, a small number of prepress and printing companies have started to use the FM screening technology in a tacit agreement to produce higher quality prints. Those art books and high-gloss catalog products with more prone moire objects, such as textile images, speaker's pupils, and architectural designs, all benefited from FM screening technology and became a technology they were happy to use.

Simplify the process

Because CtP technology can simplify the process, it plays an important role in the recovery process of FM screening technology. In addition to film, dust and registration problems have become some of the factors that hinder the development of FM technology.

With CtP technology, there is no need to think too much about film edges (thickness) or dust particles, so fewer FM dots (offset printing usually at 12 to 30 microns, flexo and newspaper printing up to 70 microns) can be printed directly Version is formed.

Another advantage of CtP technology is that a harder dot can be formed on the thermal plate for better printing results. Microparticles composed of lasers can form screen points that are predictable in imaging and printing. Any edge of the dot formed by the unfixed layer of the residual plate will not form an irregular printing effect.

Creo Corp. strongly recommends using Turbo or SquareSpot screening technology to advance the quality of hard-net sites. This technique uses a higher resolution than the secondary scanning direction in the main scanning direction to improve the accuracy of screened dots. Compared with the conventional dot-mapping (24002400dpi) technology of the same size, a screen dot composed of more particles can obtain a higher resolution effect (96002400 dpi).

Heidelberg applied this technology to their CtF imagers a few years ago, Creo formed this precise network, and the company's Staccato screening technology and consulting services combined to enable FM screening technology to recover again. It advocates controlling the profits of the machine, including reducing the amount of ink used, obtaining higher color stability and the balance between ink and ink.

Better printing process stability has shifted the offset printing from newspaper printing to 65-per-inch screen lines per inch to 100-110 lines per inch (40-44 lines per cm). In commercial offset printing, the number of screens is increased from 133 lpi (54 l/cm) to 175 lpi (70 l/cm), and very high quality printing requirements can reach 200 lpi (80 l/cm).

Alternatives to AM

A method similar to FM, which replaces the AM screening technology, is the use of very fine screen screening. This method has been widely used in Japan and is commonly used by many professional printing companies in the Western Hemisphere. This method usually uses 250-350 lpi, even higher number of lines to optimize the printing effect, through a high-density ink to achieve a clearer, more detailed effect.

Breakthroughs in the number of ultra-high-gauge lines have encountered the same problems as FM, such as harsh process conditions and the need for high-resolution scanning to generate maximum profits.

In many places in Europe and the United States, 300 dpi scans and moderately false light masks are often the default locations, while in Japan scan standards are set at 350 dpi and slightly higher levels of unclear masks to meet the requirements of higher screen lines. . Associated with the number of super-high screen lines is a higher image resolution, which means that more gray levels can be generated.

For ultra high-dual-screen 4000 dpi, the imaging process is greatly slowed down compared to the more commonly used 2400 or 2540 dpi in the Western world in AM and FM screening.

In the East, Fuji Corporation proposed a Co-Res screening method that uses the traditional screening angle, which can be compared with the use of relatively high resolution image effects. From this, a 1219dpi image can reach 175lpi. Alternatively, a 300 lpi effect can be obtained from a platemaker that has a lower image resolution and cannot obtain this effect.

To date, the technology is still limited to use in Fuji's Corporate RIP and plate makers. The most immediate advantage is that there will be a leap in the overall production volume, because there is less data to be processed, and it is not necessary to change the operating habits of the printing press, because the screen angle and dot are exactly the same as the original.

A few years ago, companies like Barco and Screen were looking for the ideal way to combine FM and AM screening on the same image. This approach uses the most suitable AM ​​screening in both flat and skin tone locations, and FM screening in fine detail and moiré-sensitive object areas.

Interactive mask

The disadvantage of the hybrid screening method is that it requires interactive masks on high-end workstations, such as Screen's TaigaPress. Therefore, the labor intensity is high, and it is only suitable for high-value printing projects. For packaging applications, printing methods with more than four colors are usually used. For coarser flexo screens, Barco and Artwork Systems have developed a corresponding hybrid screening method to not only avoid moire but also Brighter and darker areas produce more detail that can be used for clearer, more saturated printing.

This hybrid screening method provides FM details and continuous tone reproduction of bright and dark areas without affecting most flat tone and mid tone granular graphics because these are implemented using AM screening.

In the field of newspaper printing, Agfa completed the test of the hybrid screening technology Sublima, which has been tested in Norway, using FMCristalRaster outlets in some regions and AMABS screening in the middle portion.

Screen Corporation has recently introduced Spekta, a new hybrid screening technology, to achieve the best quality of its thermal CtP imagers. Spekta effectively combines the advantages of FM and AM screening in dot formation, color mixing, moiré, and ease of operation compensation on the press.

Like other hybrid screening methods, Spekta uses FM screening in 0-10% and 90-99% of replication areas, and uses AM round-network screening in the 10-90% range. Since all the dots are randomly distributed within the total network area, there is no screen angle restriction between different colors, so no moiré problem occurs when colors are mixed. Spekta provides an optical effect comparable to 300+lpi compared to other high-mesh screening methods, and there is no productivity limitation, but 2400dpi screening is required in standard image setting areas such as 175lpi (70l/cm). .

After successful testing, some European users, such as Zwaan Offset in the Netherlands and Fulmar Printing in the United Kingdom, appreciated the way in which the clear detail provided by FM Screening combined with the overall process control provided by AM Screening. Both methods are well known to printing companies.

The best screening solution

Under normal circumstances, adding text to the image will have better results, such as labels and maps. Using Screen's Spekta Screening Technology eliminates noticeable rose spots and moire, along with ScreenTaiga and Trueflow, provides users with a unique PlateRite thermal imaging machine, which is a versatile, most suitable screening solution.

After the end of the screening war in the 1980s, the industry experienced a relatively quiet period.

New technologies related to thermal CtP imaging technology can now produce clearer, more replicable dot quality. Based on this, prepress customers are constantly looking for the best screening mode to get the maximum productivity in order to achieve the best reproduction effect in the easiest way.

In the process of printing and copying, outlets are undoubtedly the key. Combining AM and FM technologies together will definitely produce better results.