How to classify printed book paper
Letter paper
The letterpress paper uses the main paper for letterpress printing of books and magazines. It is suitable for texts such as important works, scientific books, academic journals and textbooks for colleges and universities. The letterpress paper can be divided into four grades of No. 1, No. 2, No. 3 and No. 4 according to the distribution ratio of the paper materials. The number of papers represents the quality of the paper. The larger the number, the worse the paper quality.
Letterpress paper is mainly used for letterpress printing. The characteristics of this paper are similar to, but not identical to, newsprint. The paper structure of the relief paper is relatively uniform, and the gap between the fibers is filled with a certain amount of filler and rubber, and is also bleached, which forms a good adaptability of the paper to printing. Although its ink absorption is not as good as newsprint, it has the characteristics of uniform ink absorption; water resistance and whiteness of paper are better than newsprint.
The relief paper has uniform texture, no lint, slight elasticity, opacity, slight water resistance, and certain mechanical strength.
Newsprint
Newsprint is also called white paper, which is the main paper for newspapers and books. Applicable to newspapers, periodicals, textbooks, comic strips and other text papers. The characteristics of newsprint are: paper is light and has good elasticity; ink absorption performance is good, which ensures that the ink can be fixed on the paper. After calendering, the paper is smooth on both sides, no lint, so that the two sides of the print are clear and full; have a certain mechanical strength; good opacity; suitable for high speed rotary printing.
This kind of paper is made from mechanical wood pulp (or other chemical pulp) and contains a lot of lignin and other impurities. It is not suitable for long-term storage. If the storage time is too long, the paper will become yellow and brittle, and the water resistance is poor. 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 lithography.
Offset paper
Offset paper is mainly used in lithographic (offset) printing machines or other printing machines to print higher-grade color prints, such as color pictorials, albums, posters, color labels and some advanced book covers, illustrations and so on.
Offset paper is divided into special numbers, No.1 and No.2 and No.3 according to the proportion of paper pulp. There are single-sided and double-sided parts, as well as super-calendering and ordinary calendering.
The offset paper has small stretchability, uniform absorption of ink, good smoothness, tight opacity texture, good whiteness and strong water resistance. Conjunctival offset printing ink and good quality printing ink should be used. The viscosity of the ink should not be too high, otherwise powder removal and pulling will occur. Also to prevent the back side from getting dirty, generally use anti-dirty agent, dusting or lining paper.
Coated paper
Coated paper, also known as coated paper, is made by coating a layer of white paste on a base paper and calendering it. The paper has smooth surface, high whiteness, uniform distribution of paper fibers, uniform thickness, small stretchability, good elasticity and strong surface smoothness, high whiteness, uniform distribution of paper fibers, uniform thickness and flexibility. Small, with good elasticity and strong water resistance and tensile properties, the ink absorption and receiving state is very good. Coated paper is mainly used for printing albums, covers, postcards, exquisite product samples, and color labels. The pressure of the coated paper should not be too large, and the offset resin ink and the bright ink should be used. To prevent the back side from getting dirty, you can use methods such as adding anti-dirty materials and dusting. Coated paper has two types, single and double.