Paper and color effect in the hottest printing

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Paper in printing and color rendering effect

as the main raw material of printing, its performance determines the quality of printing ink. Only the paper with good performance can get better printing color effect. Therefore, it is of great practical significance to correctly understand the relationship between paper performance and printing color, and reasonably select paper for printing according to the characteristics of printing products and process conditions

I. The relationship between paper smoothness and color rendering effect

smoothness is a technical index to evaluate the concave convex degree of paper surface, and a physical quantity to indicate the flatness, smoothness and uniformity of paper surface, that is, under certain vacuum conditions, the time required for a certain volume of air to flow between the paper test sample surface and the smooth glass surface under certain pressure is measured, and its unit is expressed in seconds. The higher the number of seconds, the better the smoothness of the paper. The better the smoothness of the paper, the more uniform and complete the contact between the paper and the printing plate during printing, the more sufficient the transfer of the ink layer on the layout (letterpress) or blanket, and the better the color rendering effect of the print. On the contrary, the paper with poor smoothness has uneven and insufficient ink transfer, and the paper has strong permeability to the ink volume, so the color rendering effect is also poor, which is often easy to make the ink color of the printed products faint. Therefore, for products with fine printing, the thinner the line and the smaller the dot diameter, the smoother the paper should be used for printing, so as to make the original reproducible

second, the relationship between paper gloss and color rendering effect

paper gloss refers to the degree of specular reflection on the surface of the paper, expressed in percentage. The higher the gloss of the paper, the more the surface can reflect light like a mirror, and the more bright the appearance characteristics can be displayed. In fact, in addition to specular reflection, there is also diffuse reflection on the paper surface, which reduces the gloss of the paper. For paper with high gloss, the ink color of printing is also brighter, and the ink visual effect is also better. It can be said that the smoother the paper, the higher the gloss, and the higher the gloss of the printing color. The glossiness and smoothness of paper are closely related, but glossiness is not smoothness. The glossy surface of paper is not necessarily a smooth surface. From the perspective of the gloss characteristics of paper, it is of great practical significance to select the appropriate paper for printing according to the characteristics of printing. For example, for books and periodicals whose layout is mainly text, paper with general gloss should be selected to avoid reflection, so that the eyes will not be tired after reading for a long time. For the printing of plates, paper with high gloss should be selected to make the printing ink uniform, thick, bright and pleasing to the eye

III. The relationship between paper whiteness and color rendering effect

paper whiteness refers to the ability of paper to fully reflect after being exposed to light. It is also known as paper brightness, which is expressed in percentage. The higher the whiteness of the paper, the more accurately the ink color characteristics can be displayed on its surface. This is because white paper needs to reflect back the color light synthesized by subtraction of transparent ink layer. Therefore, the paper with high whiteness can reflect almost all the color light, making the printing ink bright and pleasing to the eye, with good visual effect. However, the paper with low whiteness only absorbs part of the color light, which is not only 3. Speed accuracy: ± 1% of the indicated value can not truthfully show the contrast between the light and dark parts, but also easy to cause color deviation. For example, some appear yellow, some appear red, some appear green, and some appear blue, etc. When the paper itself is biased, the color printed on the paper is the effect of the comprehensive color rendering of both ink and paper, so some color biases are bound to occur. Based on this situation, it is necessary to analyze the whiteness and color biases of the paper during printing. In 2015, there will be 5million new energy vehicles in the world to analyze the control originals, and the purpose of correcting color biases will be achieved by taking appropriate measures. For example, when the color of the paper is yellowish, it is not suitable to use inks with dark yellow, malachite blue and bright red for printing, that is, the ink should be correctly selected according to the characteristics of the paper color to eliminate the color deviation. On the other hand, the color deviation can be corrected by inking process

IV. The relationship between paper absorption and color rendering effect

paper absorption refers to the absorption capacity of paper to binder and solvent in ink, which is usually expressed in percentage. The absorption of paper is also called ink absorption. Its strength is very sensitive to the performance of printing hue and gloss of ink layer. For paper with strong ink absorption, the ink hue of printing is easy to fade, and the ink layer also lacks gloss. However, there are still limitations. In addition, because most of the binders in the ink are absorbed by the paper fiber tissue, the pigment particles are not adequately protected, and the ink film on the print is not firm, which is easy to cause the imprint to "pulverize". On the contrary, if the ink absorption of the paper is too weak, the ink layer of the print will not adhere firmly, and the imprint is not easy to dry, which is easy to cause the back of the print to rub dirty. Therefore, according to the use characteristics of prints, select the paper with appropriate absorption for printing, in order to better ensure the printing quality. For example, newspapers should be printed with absorbent paper to meet the characteristics of high-speed, urgent and economical use. For products with fine printing, bright colors require weak paper absorption, such as glass cards, coated paper, etc. Among the paper properties that affect the color rendering effect of printing, the most prominent is the gloss and absorption of paper. The comprehensive effect of the absorption and gloss of paper on the ink effect of printing is called the surface efficiency of paper, which can be calculated according to the following formula:

PSE (%) = (100-a (%) + G (%)/2

a) type inspection of new factory production and trial production; Where: PSE represents the surface efficiency of paper; A is the ink absorption capacity of the paper; G is the gloss of the paper. The process test shows that when the surface efficiency of the paper is high, the color intensity of the ink is the largest, while the color deviation and gray scale are the smallest under the same process conditions. The research and testing of paper surface efficiency is an important part of realizing process digitalization and standardization, and is of great significance to better correct color deviation and ensure the printing quality of products. Therefore, it is undoubtedly beneficial to correctly understand and understand the influence of several properties of paper on the color rendering effect of prints

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