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The density can be calculated by dividing the grammage of paper (in grams per square metre or "gsm") by its caliper (usually in micrometres, occasionally in mils). [1] The "ISO 534:2011, Paper and board — Determination of thickness, density and specific volume" indicates that the paper density is expressed in grams per cubic centimeter (g/cm ...
Grammage and basis weight, in the pulp and paper industry, are the area density of a paper product, that is, its mass per unit of area. Two ways of expressing the area density of a paper product are commonly used: Expressed in grams (g) per square metre (g/m 2), regardless of its thickness [1] (known as grammage). This is the measure used in ...
Set-off is measured at two different time intervals, 0.35s and 3s. A freshly printed surface is pressed against a paper after 0.35s and after 3s. Then the set-off density is measured. The idea behind selecting these two timings is to know what will be the set-off when the materials are used in a high-speed press and a low-speed press.
In the US, paper density is usually measured in "pound per reams" (of 500 sheets). Typical Letter paper has a basis weight of paper of 20 or 24 pounds (9.1 or 10.9 kg) – the weight of 500 sheets (a ream) of 17-by-22-inch (431.8 by 558.8 mm) paper at 70 °F (21 °C) and at 50% humidity. [ 3 ]
The weight of an A-series sheet of a given paper weight can be calculated by knowing the ratio of its size to the A0 sheet. For example, an A4 sheet is 1 ⁄ 16 the size of an A0 sheet, so if it is made from 80 g/m 2 paper, it weighs 1 ⁄ 16 of 80 g (2.8 oz), which is 5 g (0.18 oz).
Offset printing is a common printing technique in which the inked image is transferred (or "offset") from a plate to a rubber blanket and then to the printing surface. When used in combination with the lithographic process, which is based on the repulsion of oil and water, the offset technique employs a flat (planographic) image carrier.
Similarly, two sheets of A4 can be scaled down to fit one A4 sheet without excess empty paper. This system also simplifies calculating the weight of paper. Under ISO 536 , paper's grammage is defined as a sheet's mass in grams (g) per area in square metres (unit symbol g/m 2 ; the nonstandard abbreviation "gsm" is also used). [ 5 ]
The telephone cables have a large number of conductors that are individually insulated. The paper needs to be thin (30-40 g/m 2). A normal power cable needs more insulation and therefore paper with higher paper density is used, normally 60-190 g/m 2. The paper needs to be strong, elastic, uniform and free of holes or debris.