Classification of Paper for Book Printing

Classification of paper for printing books
1. Letterpress paper
  Letterpress paper is the main paper used in letterpress printing books and magazines. It is suitable for main text paper such as important works, scientific and technological books, academic journals and textbooks for colleges and technical secondary schools. Letterpress paper can be divided into four grades of No. 1, No. 2, No. 3 and No. 4 according to the proportion of paper materials. The number of the paper represents the quality of the paper. The larger the number, the worse the paper.
Letterpress paper is mainly used for letterpress printing. The properties of this paper are similar to, but not identical to, newsprint. The fiber structure of letterpress paper is relatively uniform, and the space between the fibers is filled with a certain amount of filler and sizing material, and it is also bleached, which forms this paper with good adaptability to printing. Although its ink absorption is not as good as that of newsprint, it has the characteristics of uniform ink absorption; water resistance and paper whiteness are better than newsprint.
2. Newsprint, also called white newspaper, is the main paper used for newspapers and books. Applicable to newspapers, periodicals, textbooks, comic strips and other text paper. The characteristics of newsprint are: the paper is light and has good elasticity; the ink absorption performance is good, which ensures that the ink can be well fixed on the paper. After calendering, the two sides of the paper are smooth and lint-free, so that the imprints on both sides are clear and full; it has a certain mechanical strength; it has good opaque performance; it is suitable for high-speed rotary printing. This kind of paper is produced from mechanical wood pulp and contains a lot of lignin and other impurities, so it is not suitable for long-term storage. If the storage time is too long, the paper will become yellow and brittle, with poor water resistance, and it is not suitable for writing. Printing ink or book ink must be used, the viscosity of the ink should not be too high, and the moisture of the layout must be strictly controlled during lithographic printing.
3. Offset paper
Offset paper is mainly used for lithographic (offset) printing presses or other printing presses to print higher-grade color prints, such as color pictorials, picture albums, posters, color-printed trademarks, and some advanced book covers and illustrations. Offset paper is divided into special number, No. 1, No. 2, and No. 3 according to the proportion of pulp. There are single-sided and double-sided points, and there are two grades of super calendering and ordinary calendering. Offset paper has small flexibility, uniform ink absorption, good smoothness, tight and opaque texture, good whiteness, and strong water resistance. Conjunctival offset printing ink and better quality lead printing ink should be used. The viscosity of the ink should not be too high, otherwise there will be powder removal and hair pulling. It is also necessary to prevent the back from sticking and dirty, generally using anti-dirt agent, powder spraying or interlining paper.
4. Coated paper
Coated paper, also known as coated paper, is made by coating a layer of white slurry on the base paper and calendering. The surface of the paper is smooth, the whiteness is high, the paper fibers are evenly distributed, the thickness is consistent, the stretchability is small, the paper has good elasticity and strong surface smoothness, the whiteness is high, the paper fibers are evenly distributed, the thickness is consistent, and the stretchability Small, with good elasticity and strong water resistance and tensile properties, the absorption and reception of ink are very good. Coated paper is mainly used for printing albums, covers, postcards, exquisite product samples and color trademarks. When printing coated paper, the pressure should not be too large, and offset resin ink and bright ink should be used. To prevent the back from sticking dirty, methods such as adding anti-dirty agent and dusting can be used. There are two types of coated paper: single-sided and double-sided.