Newsprint and Printing (I)

In color newspaper printing, newsprint is a substrate, and graphic information is presented to readers through paper. Therefore, the printability of newsprint directly affects the quality of the final printed newspaper. The smoothness, ink absorption, whiteness, mechanical properties, and dimensional stability of the paper can all affect the print quality of the newspaper.
First, the smoothness of newsprint In the printing, to obtain faithful to the manuscript of the printed matter is the first condition is the smoothness of newsprint. The smoothness of newsprint reflects the degree of microscopic geometrical unevenness on the surface of newsprint. Only with a certain degree of smoothness, can we ensure the reproduction of images and texts. The surface of newsprint has many pores and pores. To achieve the desired printing effect, that is, the print is clear, the ink is uniform, and the layers are rich, it must be ensured that the paper and the blanket are in good contact. If you want to get rich, colorful graphics, you must put four-color dots on paper as much as possible. The level of paper smoothness plays a decisive role. If the smoothness is small, the ink cannot fully contact with the paper, and the fine dots must be lost and have no layer. Therefore, the smoothness of the paper is an indispensable condition for determining the number of lines of the screen and obtaining a high quality dot. Highly flat paper can obtain enough ink, and the ink layer is uniform, the thickness is uniform, the ink transfer rate is high, the density of the printed matter is high, the dot enlargement value is small, the color is rich, and the reproducibility is strong. Paper with poor smoothness has incomplete dots, poor colors, and poor color reproducibility. Appropriately increasing the ink's fluidity, ink supply, and printing pressure can make up for the emptiness and falsehood caused by poor smoothness. However, the consequences of doing so is to cause the network to expand, dark tone paste, color cast, you can also print a lighter color, to achieve the purpose of the bottom. Therefore, newsprint must use newsprint with high smoothness.
Second, the whiteness of newsprint Paper is the carrier of graphic information, and its whiteness directly affects the color of print. When the light hits the paper, it is absorbed and the amount absorbed depends on its whiteness. The higher the whiteness, the more light is reflected. After the ink is transferred to the paper, the color is formed by the color subtracting method and the color light adding method. The low whiteness of the paper absorbs too much light, and the color of the ink cannot be fully exerted, affecting the hue, lightness, and saturation of the image color, resulting in dull colors, poor contrast, dullness of the picture, lack of vitality, and low levels.
The ink-absorbing properties of newsprint The ink-absorbing properties of paper include the transfer and penetration of ink to paper. It depends not only on the ability of newsprint to absorb the ink binder but also on the absorption of newsprint by ink under newsprint conditions. Therefore, ink absorption should be a comprehensive reflection of the performance of paper (newspaper) and ink under printing conditions. That is, the quality of ink absorption is not entirely dependent on the performance of newsprint, but also depends on the performance and printing conditions of the ink. (To be continued)