印前技术宝典3（Prepress technology collection 3）According to the different use of paper, it can be divided into industrial paper, packaging paper, living paper, cultural paper and so on. Among them, cultural paper includes writing paper, art drawing paper and printing paper. In printing paper, according to the performance and characteristics of the paper are divided into newsprint and letterpress printing paper, offset printing paper, coated paper, dictionary and sea map drawing, painting, printing paper, newspaper weekly newspaper, white paper, writing paper. In addition, some high-grade prints are also widely used in art drawing paper.Newsprint newsprint: mainly used for newspapers and some books and letterpress printing, paper soft, rich elastic plastic, ink absorption ability, have certain mechanical strength, suitable for different kinds of high-speed rotary printing machine. This paper is made of wood paddle as raw material, containing more lignin and impurities. The paper is easy to yellow, crisp and water resistant, so it should not be preserved for a long timeLetterpress paper: This is a special paper used in letterpress printing, paper properties of newsprint, water resistance, color purity, the paper surface smoothness is newsprint slightly better ink absorption is more uniform, but strong ink capacity than newsprint to the poor.Offset printing paper, offset printing paper for offset (offset) is a kind of printing paper, is divided into single-sided offset paper and offset paper surface two, single-sided offset paper is mainly used for printed posters, packaging boxes; two-sided offset paper is mainly used for printing pictures, pictures etc. Offset paper closely, scalability small, anti water ability, can effectively prevent the deformation of the paper, multicolor overprint dislocation, napping, shedding and other illnesses. It can maintain good quality and purity of printed matter.Offset coated paper: also known as coated paper, paper is coated with a layer of inorganic coatings by a super pressure light made of high-grade paper, paper surface smooth, high purity, printing can get more detailed and smooth network, can reproduce the original layered, widely applied to art pictures, brochures, leaflets and other business.Gravure printing paper: gravure printing paper is white and strong, with good smoothness and water resistance. It is mainly used for printing banknotes, stamps and other high-quality and difficult to imitate the printed matter.White paper: white paper is a fibrous tissue is more uniform and the surface layer with filler and rubber composition and surface coated with a layer of paint, a paper by multi roll calender made out of paper, color quality has high purity, uniform ink absorption, a folding degree good, mainly for goods packing box, commodity table liner, charts and other pictures.Synthetic paper: synthetic paper is the use of chemical raw materials such as alkenes and adding some additives made with soft texture, corrosion resistance, water resistance, high tensile strength, resistance to hot and cold resistance, and resistance to chemicals and no environmental pollution, good air permeability, widely used in advanced art, maps, pictures high-grade, books and other printed.4, the performance requirements of paperWhether the paper can be used for printing smoothly or not depends on the printability of the paper. Requirements for printing on paper: paper color as far as possible to achieve the same texture color purity, paper dust shall not exceed the allowable range, with minimum transmission rate, and ensure the mechanical strength of normal printing, paper thickness, compactness and structure characteristics of the same to keep in the same printing in the bulk, the edges of the paper should be right angle and the pitch error is not more than 3mm.Smoothness of the paper: the smoothness of the paper determines the printing quality of the printed matter. The smoothness of the paper in nano imprint lithography, can make contact with the layout, so that the ink layer on the plate can be evenly transferred to the paper surface smoothness, low paper, because the printing surface is not flat, causing the surface contact with the paper layout imprint is not uniform, so that the ink layer of the transfer to the the paper presents the phenomenon of uneven progress, such as touch on the smoothness of the lower paper, can be appropriately increased when printing in the printing pressure, can properly make up due to its uneven surface imprinted hair deficiency phenomenon.Such as dry vegetable oil, mineral oil, solvents and water, as well as a variety of synthetic resins. The use of ink in the process of fluidity, viscosity, acid value, neutral shade, water resistance and printing performance depends on the bonding material, the same kind of paint can be used to connect different materials to make different types of ink; connected with a material