THICKNESS : Thickness of the paper is calculated in terms of weight per square meter which is described as GSM
(grams per square meter).

BASIS WEIGHT: The basis weight of a paper is the weight of 500 sheets, measured in kilograms, in that paper's basic sheet size.

PAPER BRIGHTNESS : A paper’s brightness is measured by illuminating the specimen with a source 45 degrees to the paper’s surface and filtered at 457nm, and a photocell at 90 degrees to the paper’s surface. The instrument is calibrated using magnesium oxide, which is referenced as 100. The paper’s brightness therefore is a measurement of the ratio of reflected light from the paper to the reflected light from the magnesium oxide.

PAPER OPACITY : Opacity is the ability of the paper to block transmitted light. The instrument used to measure this property, takes a measurement of the light reflected by the sample placed in front of a white standard ratioed against a measurement of the light refle

BURST STRENGTH : Burst strength is related to tensile strength and fiber orientation. It is a test of the ability of the paper to resist bursting when placed under the pressure of a diaphragm. In the Mullen test, the specimen paper is clamped with a ring over a collapsed diaphragm, which is then filled with oil, until the paper burst. The measurement is related as the pressure applied to the diaphragm at the moment of bursting.

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