Today we will try to answer the question: “offset printing paper – what is it? Any person not familiar with the production of newspapers, magazines and leaflets can ask themselves this question, because it is most often offset paper that is used for the manufacture of such products.
What is offset printing paper anyway?
Offset paper is a cellulose material designed for offset printing of illustrations and texts on its surface. Such paper is considered to be more durable than regular paper.
It is made of pure cellulose or with the addition of wood pulp and is characterized by high strength, resistance to deformation and moisture. The stiffness of offset paper, its absorbency, measurement and calibration stability are of great importance, because the quality of the final product depends on it.
Among the features of offset paper, there are quite serious requirements for it. It must ensure high productivity of the equipment in order to be successfully used for large runs.
Coated paper is printed by transferring ink onto the surface of a special rubber fabric. Consequently, the material must have good printing and structural-mechanical properties. To make the paper more durable, it is necessary to impregnate its surface with a special mixture. It is necessary to add a large number of additives and fillers. But in no case it is impossible to overdo with these additives, otherwise they will lower quality of the material and in the process of printing the paper will not stick to the rubber surface of offset printing forms. The GOST strength values for the highest grade of offset paper should be at the level of 2200 m.
Dampness resistance
Проклейка и пропитка офсетной бумаги повышает ее влагостойкость, так что даже после намокания она не деформируется и не изгибается. Но проникновение чернил внутрь волокон приносит туда абсолютно ненужную влагу, которая концентрируется на поверхности и вымывает чернила из волокон.
If absorbance rates are not monitored, the paper will quickly absorb ink from the printing cylinder and the layer surface will change and the final print quality may be degraded. The use of some types of printing can cause changes in the structure of the dye. Thus, the depth of penetration can range from quite deep (impregnation) to surface coverage.
Wood content
As for the life of offset paper, it depends on the content of wood pulp in its base. For periodicals, it is better to use a material with about 50-75% wood pulp. If the print publication is intended to be used for a long period of time, it is better to use fiber papers.
Smoothing
The smoothness of offset paper is important. This type of material can have different surface types depending on the type of drying. There are two levels of smoothness on offset paper:
- Calendered paper with smoothness up to 150 ;
- Offset paper, machine smoothness from 30-80.
Utilizing
Offset paper is one of the main materials in the printing industry. It is widely used in the creation of advertising, product branding, in order to make design decisions. The main areas of application:
– printing newspapers, books, magazines, and other publications;
– creation of catalogs, brochures, flyers, posters, leaflets.
Manufacture of offset paper
Офсетная бумага выпускается в рулонах или листах. Продукция должна соответствовать требованиям ГОСТ 9094-89.
и делится на три группы:
– No. 1 (bleached pulp is used for printing color products with half-tone transitions);
– No. 2 (from bleached cellulose mixed with wood pulp);
– Class B (short life span).
As you can see, different, white offset paper, and composition, durability and other indicators.
Paper density
The density of offset paper is 70 – 300 g/sq. m. and is calculated by dividing the weight of paper by the area of the sheet.
We hope that you learned today: offset printing paper – what it is and when it is used.
