Discussion on Judgment and Control of Printing Iron Quality

The quality of printed iron products is inseparably related to the management of product quality by the relevant management personnel at all levels and the understanding and pursuit of the product quality requirements of the operators. It is difficult to evaluate the quality of Indian iron products. People can only make comparatively objective evaluations by comparing multiple pictures together. If you print a single print product separately, people's views on the quality of the text are often inconsistent and sometimes even the opposite. In actual operation, the product quality standards are generally determined by the customer after negotiating with the relevant business personnel of the printing company, and written into the supply contract of both parties. At present, people generally believe that good quality Indian iron products should be true and credible in color and have a variety of tone levels.

1. Iron color control

Judging from the conventional quality requirements for printing iron, whether the color is authentic or not is the key to the quality of printed iron and iron graphic quality. To be true and credible, we should pay attention to the following aspects:

(1) Pay attention to spot colors

In view of the fact that color is the most concern for customers and is the most difficult issue for Indian Railways workers, and people’s judgment on color is often subjective, therefore, the printing company staff should pay special attention to these spot colors. It is suggested that customers not only provide original documents to Indian Railways, but also provide PANTONE color numbers for the colors that need to be emphasized, which facilitates color control of printing staff.

(2) Guarantee original quality

At present, the quality of domestic originals of printed iron sheets is uneven, and a considerable portion of originals submitted by customers need to be modified or even re-made before they can be used.

If the original document needs to be scanned, you must pay attention to accurately grasp the scanning skills. Prior to scanning, the magnification of the graphic text is determined based on the actual size of the graphic text. At the same time, the black and white field calibration, Y value selection, USM setting, and color adjustment during teletext scan all affect the reproduction of the subtle levels of the manuscript. These require special attention.

If the electronic document manuscript sent by the customer needs to be revised, the prepress staff should not arbitrarily enlarge or reduce the picture and text in the computer. In particular, do not repeatedly modify the magnification and the number of screen lines. The number of screens should be determined by the graphic requirements of the printed iron products. It is not possible to use the plate-making means with a high number of screens.

(3) Pay attention to the proofing process

Printing iron proofing to determine the color number of color separation, color sequence, screen number, screen angle, printing ink model, substrate type (tinplate or other metal sheet, etc.) and the model of the printing machine and so on.

Printing iron after proofing to the customer to confirm the sample. If the customer is not satisfied, he or she should re-proof the sample based on the customer's amendments and re-submit it to the customer for confirmation. In normal iron production, Yintie workers must strictly follow the iron sample of the customer's signature. They cannot change their colors at will by subjective wishes.

2. Printed iron tone level control

An image with a complete tone level, histogram should have the same slope as the hillside, and fall into the histogram from the beginning to the end. If a vertical steep slope appears at both ends of the histogram, it means that the highlight or dark tone in the tone is intercepted, and the level of highlight or shadow tone has been lost. If the two ends of the image or the end of the image is still a certain distance from the start or end of the histogram, the image tone has been compressed.

The key to guaranteeing the tone level of printed iron products is to pay attention to the manuscript first, and the quality of the graphic and text will be directly affected in the entire process of shooting, processing, scanning and producing the manuscript. Under the premise of ensuring the quality of the original document, the level of compression must also be considered. The level of graphics and texts should be compressed within a certain range. This is because the graphic and texts are limited by the printing machine, PS plate, tinplate (or aluminum plate), ink and other materials and the iron printing process in the printing iron production.

As far as Indian iron printing machines are concerned, the equipment conditions of domestic printing iron companies are different. Generally divided into two categories, namely imported iron printing machine and domestic iron printing machine. Imported iron printing machine also has British and Japanese production points, mostly two-color printing machine, its material, overprint accuracy and consistency of the three roller line speed Are at the leading level. The domestic iron printing machine is slightly inferior to the above three indicators. Therefore, considering the printing machine alone, the amount of compression at the graphic level will vary from machine to machine.

In addition, the backwardness of platemaking means that the amount of compression at the graphic and textual level is slightly greater, and the amount of compression for advanced platemaking means is smaller.

In addition, the quality of the ink will also affect the graphics level of compression requirements. Relatively speaking, the ink of imported or wholly-owned enterprises is better, mainly because the pigment particles are fine, the coloring power is good, and the color is relatively pure. When the ink is used for printing, the graphics and text layers have a small amount of compression. The ink prices of domestic or joint ventures are relatively cheaper, but there is still a certain gap between ink performance on the whole, and there is a large amount of graphics and text compression.

In the compression of the tone level, it is also necessary to ensure that the high-light part of the printed iron products is not netted, and the dark tone is not combined. The increase rate of small and medium outlets in actual production is much greater than that of large outlets. For example, 2% of the small outlets are either lost in the printing iron or are increased to 6%—8%; if the highlights are set to be net-free, then the next level will automatically jump to 6%—8%. Obviously, no nets It is a striking white spot. Therefore, we must try to avoid netting. In addition, the level between middling tone and high school tone is also a point to note when printing iron.

In short, the true and credible color and the complete tone hierarchy are two important indicators to measure the quality of the graphic and text. In the production of printed iron, it is necessary to truly understand the specific requirements of graphic quality; clearly know the various factors affecting the quality of graphic reproduction; determine the tone control of the graphic according to the actual production data specification. The quality control of Yintie is a complete system project, and the digitization and standardization of Yintie’s production is the foundation of this system at any time. Establishing and improving modern Yintie management system is the fundamental way to solve the quality fluctuation.