Printing machine characteristics document printing (on)

Is digital proofing difficult? Certainly many people say it is difficult! Actually, I think it's not difficult to use the software for the operation of the instrument, but it is really difficult to establish a perfect and accurate digital proofing system! It's hard to say because it's difficult to establish it in a standard process. Everyone knows that the purpose of digital proofing is to simulate the color space of our printing press. How many people thought about your simulation in the process of simulation? Is it standard for printing presses? How is it characteristic? Imagine if our ultimate object is constantly changing then what value does this simulation have? So the establishment of the digital proofing system is actually a standardized printing process! A digital proofing that has left the press standardization will always fail.

In other words, once a standard digital proofing system is established, the standard of the printing press becomes digital, standardized, and visualized because of digital proofing.

If you understand this point, then when we do the printing machine feature file is not simply an IT8.73 file so that the printing press can be measured on the use of just to generate ICC so simple! Of course, how to establish a printing standard seems to be the job of a printing factory. I am not here to talk to you about how to establish a printing standard for printing. I just want to talk about how to do a standard digital proofing. The standard characteristics of the press used.

First, it is not difficult to get the film of standard IT8.73. It is not difficult for everyone to engage in the prepress. Emphasizing this point is to hope that everyone has a deeper understanding of the standards of the film. It is most directly related to the standardization of printing. Management, when outputting IT8.73 files, must test the maximum density of the photo-composing machine. The maximum density of the photo-distributor output film must be guaranteed to be above 3.8! At the same time, in the graph range of IT8.73, the difference between the left and right densities is less than 0.05. Then, the linearity of the imagesetter is corrected to ensure that the film linearity error of the output film is less than 1%. Finally, the bottom ash of the film is strictly controlled, and the bottom ash value is required to be less than 0.04.

Second, correctly adjust the printing time and processing conditions, pass the printing test strip: 2% of the outlets are required to be visible, 3% of the outlets are intact, and the red version of the gray staircase is guaranteed to be white. The condition can be measured by printing plate density meter after the loss of printing, it is best to ensure that 50% of the dots on the printing plate is not less than 45%.

Third, determine the printing paper and ink, generally a printing plant will have different paper types and ink types, different paper and ink will have different printing effects, can be done separately, you can also choose the most representative of the copper paper and the most Commonly used ink to do it.

Fourth, to determine the correct printing color sequence, usually the printing color sequence is arranged according to the viscosity of the ink, the most viscous ink is the first printing, it has the strongest adhesion to the paper, it can prevent the back of the ink from Paper peeling, the viscosity of the modern four-color offset printing ink from strong to weak is KCMY, so our preferred color sequence is also true, but since we know that the ink adhesion on the paper is not only the ink itself, the paper is also A decisive factor is that the acidity and alkalinity of the paper is directly related to the problem of drying and adhesion of the ink. Since the viscosity of the ink is relatively close to that of C and M, the influence of the paper on it will be great if CM two-color overprint occurs. Failure, then you must consider replacing the printing sequence that is more suitable for the paper, such as the KMCY arrangement

Fifth, the next most important step is to adjust the press before printing IT8.73. As a prepress person, we don't need you to operate the press, but you must not understand the printing principle! Knowing the principle of a printing press is always the pursuit of a qualified prepress person! How to adjust the printing press here is not our priority. This should be a matter of printing presses, but we must know what the result is and what we want. The state of the press is normal and standard. How is a standard colour standard printed?

The first task of printing is the reduction of dots, so a good print should be judged from the following aspects: 1. The best shape of dots, 2. The maximum amount of ink received by paper, and the maximum density of three or four colors in the field. 4, the minimum dot gain, 5, the best gray balance performance, 6, accurate overprint accuracy.

1, dot shape, the process of printing is the process of copying a dot, all the colors are restored through the dot, then to ensure that the film on the film is the most accurate point of the printing is the ultimate goal of printing, of course We must know that the ink is transferred through the blanket and the pressure. Under the effect of pressure, the ink on the dot must be squeezed to cause the ink dot shape on the paper to expand and deform. This is the objective existence of offset printing. While acknowledging this objective fact, maximizing efforts to control and stabilize this change is our fundamental goal in the standardization of printing presses.

It is required that outlets should be filled with four corners of a diamond shape, and 50% of the outlets should not be observed because the four corners of the 50% outlet will not be linked together due to exposure after the printing.

Let's talk about the maximum amount of ink received by paper:

2. The maximum ink-receiving capacity of the paper : The maximum ink-receiving capacity of the paper is related to the darkness level of the printed matter and the ink layer saturation of the printed product. It is also the most important means of guaranteeing the dark color space of the printed matter. In the dry condition, the maximum ink volume of the paper is better.

We can find the black ink in the column of the column where the density has just occurred, such as 92%, by means of the naked eye and the instrument. Then in this column, we compare the density and the level, such as the same density of 358 and 347, but the density of 336. Smaller then 347 is the maximum amount of ink we want, so we can use the black density=92 and the maximum ink=347 as the maximum black ink volume and maximum total ink value of our presses, and the maximum total ink amount. The maximum black ink volume is also an important parameter to be used when we want to generate the ICC characteristic curve. Of course, the maximum amount of ink is also subject to a large constraint is the drying speed of the ink on the paper, too much ink will bring difficulties to the printing press operation, such as the occurrence of drag flowers, ink and other printing failures!