The control of the effect of the film in the pre-press plate making

Film plays an important role in pre-press making. The quality of the print has been determined when it was released. Therefore, it is very important how to select and use the film to achieve the best output.

The products of well-known printing film manufacturers in the world have undergone rigorous testing before they are launched, and they are guaranteed in terms of overall quality and stability. The production of photosensitive materials also requires many years of accumulation of scientific research and production technology. If the film companies have relatively strong scientific research, production, management, and market experience of the photosensitive technology, the overall performance of the film will be more fully guaranteed.

Choosing a reputable brand often allows you to do more with less. Manufacturers who pay great attention to brand reputation are fairly standardized in terms of quality control of the film. Users find that the card has been reported incorrectly, the film is miscut on both sides, the coating is uneven, scratches and static electricity. The probability of many issues such as high film haze is low, not only improving your work efficiency, but also reducing the contradictions that arise with the user's output quality.

When you choose a film, the next thing to do is how to achieve the best output. This is not only related to the film, but also has a great relationship with the use of the film. Such as the familiarity with the performance of the film, the image-setter setting, the setting of the printer, the setting of the developer fixing conditions, etc. The reason for these settings is closely related to the role of the printing process and the film in the whole printing process.

The core role of printing is to copy a large number of originals. The purpose is to make the information contained in the original quickly and accurately. The process is to transfer the graphic information on the printing plate to the printing media such as paper on the printing press by the transfer of printing ink. In the prepress, the fully digitized graphic and text information in the computer is transferred to the film by the RIP and the imagesetter. The graphic information on the film is transferred to the printing plate through printing. Therefore, in the overall prepress to the printing process, the film bears the role of an intermediary that accurately and accurately conveys graphic and textual information and plays an important role in the printing process.

The two most important parameters in platemaking are: film density and linearization.

The density of the film is high density and low density. Low density refers to the density of the completely unexposed areas after the film is washed, generally around 0.05. The low density makes the film clear and transparent, and the quality of the printing screens is good. High density refers to the solid density after the film is actually washed at 100% exposure. In general, printing plate for coated paper printing requires high density of not less than 3.5, usually between 3.8-5.0, ensuring that the image information on the film is well transferred to the PS plate during printing. When newspaper newsprint paper and offset paper are printed, there are special printing requirements due to the strong ink absorption and high-speed printing, and the high density requirements are low. Film output requires high density stability during production.

Linearization refers to the process of color separation and plate-making. It is required to ensure that the dot value set in the computer can be truly reflected on the printed film. Taking 50% neutral ash as an example, the actual measurement on a printed film must be 50% at the place where 50% of the web sites are on the computer, and the dot error should not exceed one outlet. When the dot error is large, it will cause a great distortion of the printed image, which is particularly evident in color four-color printing. A more rigorous output center will take measurements and perform linearization corrections every day. This is mainly because the stability of the developing and fixing conditions of the film is difficult to guarantee.

Since the density will affect the linearization test, the density should be stabilized first. With Kodak's new generation of high-temperature rapid film Gen5 film as an example, the density of the best stable in the 3.8-5.0 between the best, the general domestic customers set more than about 4.2. In general, the output center should be equipped with a density meter to measure the density of the film and whether the dot is within the controllable range at any time.

Source: Comin Media