Generally speaking, the relationship between the number of grams of copy paper and the thickness is not great, but is related to the density. The so-called number of grams is calculated in square meters; 70g or 80g is not for A4 copy paper, but the gram of 1 square meter copy paper. In other words, the gram of copy paper is cut to A5, which is still called 70g or 80g; 70g paper is commonly used as printing paper and copy paper, while 80g paper is relatively small, which is a relatively high-grade printing product, and is often used for single print production such as bidding documents.
The weight of copy paper is usually expressed in two ways, one is quantitative, the other is weight.
Quantitative is the weight of copy paper per unit area, expressed in grams per square meter. It is the basic basis for measuring copy paper. The minimum quantitative of copy paper is 25g / square meter, and the maximum quantitative of copy paper is 250G / square meter. Quantitative analysis is divided into absolute dry quantitative analysis and air dry quantitative analysis. The former refers to the quantitative measurement under the condition of completely dry and water equal to zero, while the latter refers to the quantitative measurement under the condition of water balance under a certain humidity. Generally speaking, the quantitative measurement refers to the latter. The quantitative measurement should be carried out under the standard temperature and humidity conditions (temperature 23, 1 degree above or below; humidity 23, 1 degree above or below); The relative humidity is 50% and 2% respectively. |