Basis weight is the weight of a ream (500 sheets) of paper based on a standard size, which varies depending on the paper type.
It's measured in pounds in the U.S., but grams per square metre (GSM) in the UK.
The basis weight gives an indication of paper thickness, and therefore, its durability, opacity, and suitability for a specific print job.
A higher basis weight suggests a heavier, sturdier paper.
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