Stamp gravure printing technology 2

(1) Background In the printing of stamps, the background has two different manifestations. One is the background often appearing on the stamp image as a background of the motif. Although it is not the subject of the picture, it is in the entire picture. It plays a very important role in the topic and directly affects the artistic effect of the stamp. In order to make the stamp color of the finished product after printing in large quantities basically the same, there is no obvious color cast phenomenon, can perfectly reproduce the designer's artistic conception, this kind of background color generally adopts trapping printing.
When encountering a background with a dark background or a large stamp area (such as a small sheet), it is also necessary to design two color shades, dark and light, that are similar to the color to be printed. Consistent with the original color, the ink layer is thick, flat, does not spend, does not leak white point, can truly reproduce the artistic effect of the original.
There is also a background color in the pre-press design, in order to facilitate the printing control of hue and to make up for the color difference between the printed matter and the draft, the stamp color part of the artificially added background, it is also the use of spot color printing. This is because the manuscripts of the stamp designs are often selected from Chinese paintings, gouache paintings, and oil paintings. The recent works of art are very beautifully designed, with rich colors and vivid changes in levels.
If you choose to use this kind of transcript to copy the stamp, if you simply use the three primary colors plus black overlay to reproduce the picture, the color of the stamp picture will appear monotonous and much thinner than the original, often giving people a feeling of lack of color, which is inferior to the color of the manuscript. Rich and thick, the changes between colors are also more rigid and uncoordinated. The scenes on the screen are also plain and rough, and the artistic effects of copying are not ideal.
On the other hand, from a printing point of view, if the postage stamps completely rely on the superposition of the three primary colors to produce a change in color, it is difficult to make the face-to-face hues of large-volume prints consistent.
In this case, in order to be able to perfectly reproduce the artistic charm of the manuscript and obtain a high-quality stamp product, the process design is based on the main colors of the original picture, and one or two spot colors are used as the background color of the pattern portion. Pavement, which is the complement of color, such as: dark, light gray, dark, light yellow, purple, etc., plus the three primary colors. In such large-volume printing, the main color of the ticket surface is fixed and fixed, and the ink color can be relatively uniform, ensuring the printing quality. At the same time, the artistic effect of the stamps has been greatly improved, making the tone basically the same as the original. It also reproduces the blooming effect of the original color. The color is rich and soft. The color changes naturally and harmoniously. The whole picture is smooth and delicate.
(2) Skin color of the character The skin color of the character, especially the skin color of the face, is an important part of the character pattern, and is also the main rendering part of the art design. This is also crucial in the printing of other books and advertisements. And it is even more prominent in the imprint of the stamp. As the area of ​​the stamp is small, the area of ​​the face complexion is even smaller. If three primary colors are used for overlay printing, it will bring certain difficulties for overprinting and ink control.
After mass printing, the face color of finished stamps often appears color cast, some reddish, some yellowish, and inaccurate overprinting, facial contours will also be deformed. In particular, stamps on the subject matter of characters, if the subject person's facial skin color is inconsistent, or the outline is unclear, it will affect the image of the character, directly affect the artistic effect of the stamp, of course, has greatly affected the quality of the stamp.
Therefore, in the process of design, according to the skin color hue of the manuscript, a spot color is generally used as the main color of the skin color, and then the three primary colors are added to set the level, so that the color of the printed skin color of the stamp part does not change much, overprinting is accurate, and the facial contours are clear. The transition of levels is natural and soft.
(3) Neutral grey Neutral gray is a mark for testing the balance of three primary colors in printing. Therefore, there is a certain technical difficulty in the reproduction of neutral grey in the printing, especially light neutral gray, and its color change visually. More sensitive, the proportion of three primary colors is slightly different, and the hue is far from one another.
In high-volume batch printing of stamps, if three primary colors are used to reproduce neutral grey, the technical difficulty and labor intensity will be high, and the final product pass rate will be low; the neutral gray color will be on the face of the ticket. Color cast.
If the standard of finished product quality inspection is not properly grasped, it will cause confusion to the philatelic market. In order to avoid the above phenomenon, in the process design, the neutral gray part of the ticket is generally printed with a spot color gray. Such stamp products printed in batches before and after batch printing will not have any difference in the hue, which can greatly improve the qualification rate of finished products, at the same time shorten the production cycle and save raw materials. (Finish)