Using CTP Screening Technology to Improve Printing Quality (II)

Combination scheme one

The scheme divides the image into several parts. At the details, random dots are adopted to capture the subtle differences in the hue. The flat net uses amplitude-modulated dots to achieve a flat mesh effect without noise. However, this solution takes longer to calculate, and therefore reduces productivity. In addition, traces at the junction of the AM and FM sites are clearly visible, making the reproduction unnatural.

Combination scheme two

The program uses AM sites to process midtones and uses FM sites to handle bright and dark tone. With this method, the amplitude modulation net points can achieve a soft reproduction effect, and with the application of a high resolution, fine parts can also be visualized. FM outlets can ensure that outlets are not too small, beyond the processing power of plates and printers. In order to avoid variability, the number of dots can be reduced, but the traces at the junction of the AM and FM dots are also clearly visible, making the reproduction unnatural.

Combination scheme three

The scheme distributes amplitude modulation network points through the frequency modulation method, and the detail reproduction effect is good and the frequency is moderate. However, the defects inherent in the FM network have not been overcome, and particles will still appear in the intermediate tone and the peace network.

Overclocking technology

In order to obtain an automatically generated and realistic natural high-resolution network cable, it is necessary to integrate different technologies. The overclocking screening technology uses FM mesh points to capture details in the bright and dark tone areas, and uses amplitude-modulated mesh points to achieve a smooth gradient in the middle tone area. In addition, to achieve a smooth transition at the point of transition, we must also take into account the printing limit of the printing press.

In fact, the overclocking screening technology uses the FM outlets in the bright and dark tone areas, and uses the AM outlets in the middle tone to achieve a smooth transition at the outlets. Accurately calculating the image is no longer limited to switching between the AM and FM mesh points. For example, when reproducing a highlight zone, the AM dots will gradually become smaller to the minimum size that can be copied on the fly, and then fade out to replace the FM dots. In the same way, the dark tone area is also a smooth transition from one type of point to another, leaving no trace at the junction. The dots in the highlights and shadows may appear to be random, but not truly random. The FM network area uses a small dot network under the control of the FM mode. It is arranged in a certain angle line shape, which becomes the extension of the AM channel line to determine the angle of the AM cable. As a result, a brand new dot arrangement emerges, so it is named overclocking and screening.

Overclocking screening production capacity and printing performance

Overclocking screening technology can complete a 180-line/inch network cable reproduction with a resolution of 1270dpi. When the maximum dot-line number is 340 lines/inch, the required resolution is only 2400dpi. The printing press is a part of the image reproduction system. The overclocking screening technology is used as a guideline. In fact, there are platesetters, plates, chemicals, printers, blankets, inks, and paper that need to be considered. In the prepress process, it is necessary to create the tone curve required for each production network cable. The commonly used production line number is 210 lines/inch, 240 lines/inch, 280 lines/inch and 340 lines/inch.

The traditional AM outlets are better than FM outlets, and the printing process is more stable and more tolerant. Because overclocking screens are similar to AM screens, prepress operators can move, adjust, and preserve color as they would with traditional AM booths. However, with the increase of resolution, the stability of the modulation sites in the bright tone and dark tone areas will decrease, and the performance of the FM tone points will be reversed. Overclocking screening technology combines the advantages of both and extends the range of on-board stability.

When the number of lines is 340 lines/inch, the minimum screen point for over-screening is not less than 2% of the screen points with 175 lines/inch, so the detail and smooth transition can be easily reproduced during printing. No matter how fine and complex the image is, it can be easily completed, and it can avoid the appearance of typical defects such as moire when imaging AM sites. Even if the distribution of the dots is so fine, mixed color dots will not appear on the color image and the flat screen surface, and they will be created with C, M, Y, and K primary colors. The overclocking screening technology utilizes AM outlets to overcome the shortcomings of non-responsive color changes in the FM network, maintain gray balance, overcome the limitations of the ink sequence, and the effects of changes in speed and temperature.

Sublima first real-time overclocking screening technology

The company's invention patent, Sublima, was the first to implement overclocking screening technology. Sublima developed and used two Agfa technologies—ABS balance network technology and CristaIRaster FM outlet technology.

Agfa's development of Sublima aims to optimize the system using existing printing conditions. Based on different market applications and applications, Sublima's network sites are optimized to accommodate different press and paper characteristics, including newsprint and flexographic printing, as well as commercial sheetfed and web printing. Once Sublima has determined the smallest and most easily replicated on-premises point for a variety of applications (eventually becoming the smallest dot that Sublima can generate), dots will no longer be smaller. For commercial use, Sublima can generate 210 lines/inch, 240 lines/inch, 280 lines/inch and 340 lines/inch.

Beta Sites from around the world conducted tests on Sublima and concluded that: 1) The network cable is not obvious; 2) The network cable is fine, and even thin fonts can be processed with four-color overprinting method. The printed results obtained are clear and sharp; 3 Solid and color reproduction is uniform, no roughness, color mixing without traces; 4 skin texture smooth texture, color accuracy; 5 zoom in or out without affecting the image details, the quality of the same; 6 the technology also expanded the availability of high resolution Paper types range from high-gloss coated papers to newsprint and translucent kraft paper.