Physical Fabric Tests: GSM, Strength, Abrasion, Pilling and Skew

Colour and hand are easy to judge by eye; durability is not. Whether a fabric will survive wear and washing is decided by a handful of physical tests, and a brand that names them upfront catches a weak or wrong fabric at approval instead of in a returns pile. Here are the tests that matter and what to spec against each.

Weight: GSM, the number everything hangs off

GSM (grams per square metre) is a fabric's areal weight and the single most-quoted spec. It drives hand, opacity, warmth, drape and cost, and it is the first thing to confirm on bulk because mills drift. It is measured by cutting a known area (a GSM cutter punches a set circle) and weighing it. Spec it with a tolerance - e.g. 180 GSM ± 5% - because no roll hits the target exactly.