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[Descrição sumária]1.Basis Weight: It refers to the weight of paper per unit area, expressed in g/m2, indicating the weight per square meter of paper. The basis weight of paper determines its physical properties such as tensile strength, tear resistance, compactness, stiffness, and thickness. Therefore, producing prints corresponding to the equipment's characteristics can reduce consumption, improve product quality, and enhance equipment efficiency.   2.Thickness: It indicates the degree of thickness of the paper, usually measured in millimeters (mm). Thickness is closely related to basis weight and compactness. Generally, thicker paper has a higher basis weight, but the relationship between the two is not absolute. Some papers, although thin, have an equal or greater basis weight than thicker ones. This indicates that the tightness of the paper's fiber structure determines its basis weight and thickness. Uniform thickness across paper quality is crucial for effects like automatic paper feeding and glue application uniformity.   3.Compactness: It refers to the weight of paper per cubic centimeter, measured in g/cm3. Paper compactness is calculated based on basis weight and thickness using the formula: D = G / d * 1000, where G represents the basis weight, and d represents the thickness of the paper. Compactness measures the degree of density of paper structure. If the compactness is too high, the paper is prone to brittleness, reduced opacity, decreased water absorption, and slower drying. The thickness of the paperboard can also be easily calculated using the formula: d = G / D. For example, to find the thickness of 500g/m2 double greyboard paper (with a specified compactness of 0.625g/cm3), the calculation would be: 500g/m2 ÷ 0.625g/cm3 = 0.0008m = 0.8mm. It's essential to remember the conversion between cm3 and m2 units to avoid confusion.   4.Stiffness: It indicates the paper's resistance to being crushed by another object and is a manifestation of the paper's fiber structure's rigidity.   5.Smoothness: It refers to the degree of unevenness on the paper surface, measured in seconds. Smoothness can be measured and is based on the time it takes for air with a certain solvent to pass through the gap between the glass plate and the sample surface under certain vacuum and pressure conditions. The smoother the paper surface, the slower the air passes through; conversely, the rougher the surface, the faster the air passes through.     6.Stretchability: It refers to the dimensional variation of the paper caused by moisture absorption or loss. Papers with softer fiber structures and lower compactness have higher stretchability, while those with higher compactness have lower stretchability.   7.Moisture Content: The moisture content in the paperboard, usually measured in percentage. For double greyboard paper, the moisture content is typically 8-12%.   8.Grain Direction: It refers to the orientation of the paper fiber structure. During papermaking, fibers align in the direction of the paper machine's movement, known as the grain direction. It can be identified by the sharp angles of the wire marks. The direction perpendicular to the grain direction is called the cross direction. Papers with longitudinal grain direction have lower deformation values, while those with transverse grain direction exhibit larger dimensional variations during use.   9.Porosity: Generally, thinner and less compact papers have higher porosity. Porosity is measured in ml/min (milliliters per minute) or s/100ml (seconds per 100 milliliters), indicating the amount of air passing through the paper surface in 1 minute or the time required to pass 100ml of air through.   10.Recto and Verso: During papermaking, pulp adheres to the wire mesh and undergoes dewatering to form paper. As a result, one side of the paper has a coarser texture due to the loss of fine fibers and fillers with water drainage, while the other side, without contact with the wire mesh, remains smoother. This creates differences between the recto (front) and verso (back) of the paper. Despite drying and calendering during production, differences between the recto and verso may still exist.