The theoretical part of the thesis is centered on classification and function of packaging, with the emphases on the flexible packaging. In addition, the thesis describes how the offset machine and its main parts operate, especially the varnishing unit of the machine. Moreover, the structure and traits of paper and paperboard - the most commonly used materials for the production of the flexible packaging - are described in detail. Furthermore, the thesis describes the properties of paper and paperboard based on grammage and coat. In addition, the thesis describes the structure and types of varnishes in detail, as well as the processes of drying the varnish. The experimental part of the thesis is centered on the mechanical properties of different paperboard that has prints. Paperboard was polished with a water-based varnish and UV coating. The static resistance of three types of paperboard with different grammage and thickness was measured by the Lorentzen & Wettre Bursting machine. Taber method was used to determine the bending stiffness of the three types of paperboard with different grammage and thickness. In addition, the mechanical properties of varnishes that were used for polishing were tested. Hanatek RT4 Rub & Abrasion Tester was used for a rub test. The prints were exposed to different pressures and rotational speed. The results were processed in Excel and the appropriate tables were given. The software Origin pro 8.0. was used for graphing and data analysis.