Printing News
The picture album printing paper several matters needing attention
The picture album printed matter is a kind of on the visual impact of goods and works of art, its quality good or bad depends on many factors, paper characteristic is undoubtedly one of the important factors. Good performance of paper, can fully complete ink transfer, and make clear and full to reappear in the paper, so as to achieve satisfactory print effect. But as a result of paper and other materials and technology factors limit, most color continuous tone image not faithful copy and reproduction, and can make the printing image as approximation in manuscript.
A, paper characteristics on the influence of the print gloss
In the printing process, the ink film transferred to the paper surface, and fill the paper, the uneven surface of the printed matter is quite smooth. Printing ink film surface light mirror determines the size of the print gloss, and ink film surface and is closely related with the paper properties.
1. The ink film thickness
The ink film thickness is the main factors of influence print gloss. In the paper the maximum absorption ink link material after, the rest of the link material still retained in ink film, it can effectively improve the luster of the prints. The ink film thickness, the rest of the links to the more, the material is helpful to improve the luster of the prints. The study found that: gloss with the ink film thickness increase tendency, because of different paper and different. Figure 1 for the same ink in four different paper printing on print gloss and the ink film thickness of the curve. From the picture can be seen, although ink the same, but different paper by the formation of the print gloss with the ink film thickness and the change trend is different. High gloss coated paper in the ink film is thinner, the print gloss with the ink film thickness reduce with the increase of the, this is because the ink film covered up the paper itself the original high gloss, and ink film itself the luster of the formation and the paper absorption and reduce. With the ink film thickness increases, the paper itself the original high gloss the harder it is reflected through the ink film. When the ink film thickness to 1.5 u m, paper to link the absorption of material basic saturation. After that, along with the ink film thickness of the continue to increase, retain the more links material, luster will improve. Coating board prints in the ink film is thinner luster with ink film thickness increase increased rapidly in ink film thickness increased to 3.8 u m later, luster and no longer with the ink film thickness increases. But no matter what kind of paper, gloss with the ink film thickness increased with the amount of should have a certain limit.
2. Paper characteristics on the influence of the print gloss
Paper due to fiber mixed and the formation of capillary network structure, with a large number of pore, become the foundation of ink absorption. Paper capillary network of ink link material absorption time and link material sessile time depends on the balance between print gloss formed links material penetration degree. General print gloss are with paper absorption ability enhancement and reduce.
Paper smoothness and gloss effect itself print gloss. Smoothness high beneficial to form uniform smooth ink film, so as to improve print gloss. The paper is a good luster, can improve the reflectivity of ink film, especially for transparent ink is even more so. Two kinds of ink printing in four different gloss coating paper results. From the diagram shows, two kinds of ink print gloss with the paper itself is the improvement of gloss and improve. Print gloss and luster of the relationship between the paper itself than print gloss and paper absorption ability of the relationship between the still strong.
From the above discussion, it can be found that the paper smoothness and gloss and absorptive capacity there is correlation between. From the papermaking process is easy to explain it. For example, calendered can improve paper smoothness and gloss, but also reduce the paper void content, thereby reducing paper absorption capacity. In addition, the paper surface pH value is also print gloss formed a nonnegligible factors, pH value high, be helpful for ink dry, so as to improve the luster of the prints.
Second, the paper features of printing image representation of the gradual influence
The gradual return is ideal for high quality printing image is the most important process, most of the bad print is due to the gradual representation problems cause.
Image copy the first requirement is copied on the vision of image matching with original. But in fact most of the cases is impossible to realize. Table 1 lists the different types of paper copy image density range, and the density of the original scope in 0 ~ 2.7 (3.0). Obviously in most cases, the original manuscript of the density range than printing image density range, and with a drop in the quality of paper, replicable density range is smaller, for the color saturation and so it is.
Settlement method is to compress the original order tuning range, make its and paper can recreate the density range phase matching.
Third, the paper features of network increase a lot of influence
1. Network increases
Network to increase the impact of the changes that copy hue than any other variables are big. In the paper printing ink quantity will affect network increasing, while increasing network will influence the printing contrast. In printing black and white or colour * * * eye tone image, increase network will change the image contrast and cause the loss of image detail and resolution. In multicolor printing, increase network will lead to loss of contrast, image deep dark, network paste die and cause a sharp color changes.
2. Paper features of network increase a lot of influence
Ink smooth surface in high quality paper produced the best field density, when paper quality, reduce the ink density is reduced, produce certain network expansion, affect the quality of printed matter.
Line number is higher, the smaller the diameter of the network, the paper small pit can distort or omissions small plate outlets. Therefore, the higher the number of line of fine printing paper smoothness, the higher requirements. This paper is to choose a principle. But in the actual work, also can appropriate adjustment of the ink some performance or change process parameters to adapt to the characteristics of the paper.
Four, paper printing overprint features of the influence of accuracy
For the fine print, register the demand is higher, general permissible error in the 0.05 mm inside. Multicolor printing, causes the misregister for many reasons, but in the process of printing paper for moisture content change and produce paper deformation is an important factor.
As is known to all, paper moisture content change not only results in paper expansion or contraction, and because the water content changes made paper local size changes, resulting in other forms of deformation, such as curly, collop, etc. The serious influence on the deformation of the various printing workers is concerned with the relative humidity on paper the effect of water content.
(1) must be at room temperature, high humidity changes when the relative humidity of the water content rate than when the humidity change of relative humidity of cause water content rate much larger; Low humidity is also so. From this perspective, printing in moderate humidity conditions the most advantageous.
(2) both form a closed hysteresis loop, this phenomenon is called the paper wet hysteresis. Performance: a relative humidity conditions of water balance of paper, if then through moisture absorption (moisture), back to the original relative wet environment, the water content in the air than the original to increase (decrease).
In order to make the moisture content of paper in the whole paper keep uniform, and the temperature and humidity of the printing shop to adapt; At the same time, in order to make the paper on the environment humidity sensitive degree reduced, improve paper size stability, in general, before printing to wet (hanging air) processing.
(Gold Printing Group)
? 1999-2015 All rights reserved.