Special gravure. Several special gravure processes that have been used in the printing of stamps in our country are some of the new techniques derived from the gravure printing techniques researched and developed by the stamp printers. They have unique styles and interesting differences.

Lithographic printing is done after photolithography, also known as offset printing. It has two characteristics: First, the ink pattern of the printing plate is in the same plane with the blank part. The principle of oil and water incompatibility is used. That is, the pattern is partially oleophilic and the blank part is hydrophilic and inkless. Mechanical pressure printing. Second, the pattern of the money version is first printed on the rubber under the mechanical pressure, and then transferred from the rubber cover to the paper surface. Therefore, it is also called an offset plate.

Relief printing is photocopying and printing with copperplate printing. Its printing is exactly the opposite of gravure, where the ink pattern is partially raised and the blank part is concave. The pattern of relief printing is the same as that of the lithography, and it is also the representation level of the dot size. The text and the background color are generally not printed and printed in the field. Because the pressure of letterpress printing is heavy, it often leaves traces of ink spillage at the edge of the print pattern, which is one of the characteristics of the identification of the letterpress stamp. Observed with a magnifying glass can be seen very clearly.

Photogravure is also called photocopying. It has the advantages of fine mesh and deep printing. It can produce vivid and rich colors, rich and delicate layers, and strong expression ability. It is the most commonly used printing for stamps printed in countries all over the world today. One of the methods. The gravure net pattern is different from the offset and letterpress. The former has the same dot size, and the dot depth expresses the level change; the latter two are based on the size of the dots. Observed with a magnifying glass can see a clear difference. Also stamps printed by gravure, due to different artistic design and printing process, each country has its own characteristics.

The original version of the engraving printing is an engraving artist's use of lines and dots to represent the shades of light and shade, and it is hand-crafted on the steel plate. The printed line on the paper shows a clear line point. When viewed with a magnifying glass, the sculpted line has a blade like a brushstroke like an embossed blade. When the finger is gently stroked on the paper, the outline of the image is clearly raised. Engraving printing is not only an art of print, but also difficult to copy and forge. Therefore, it is the ideal method for printing banknotes and stamps.

Engraved and gravure mixed overprint. Although the engraving printing is rich in print-like artistry and can prevent counterfeiting, it is difficult to express rich colors and delicate levels, and gravure can just make up for this defect. Photogravure also has its disadvantages. Dark prints and large amounts of ink, and the ink is a very viscous liquid. Using volatile toluene as a solvent, it often shows irregular water marks at a deep level and destroys the stamp sheet. The fine and beautiful appearance; In addition, due to gravure printing pattern, all are composed of different depths of the network, so in the thin lines or fine words, often presents a zigzag broken point, affecting the printing effect is smooth and complete, The gravure gravure exactly uses its rough and straight lines to supplement some of the incompatibility of gravure. In order to make stamps more perfect, people use the method of engraving and photogravure gentle overprinting, and exert the advantages of this printing method on the process. The two complement each other and compensate each other for better printing results. .