Most buyers start a fabric conversation with GSM and composition. Both matter, but they're the result of decisions made much earlier, at the spinning mill. The fiber that's chosen, how long it is, how it's spun and how fine the yarn is will shape the feel, strength, pilling and price of your garment before a single loop is knitted.

You don't need to become a spinner to source well. But knowing a few basics will help you read a fabric spec, ask the right questions and understand why two fabrics that look the same on paper can behave very differently.

Fiber: where it all starts

The fibers we work with most fall into two groups. Natural fibers like cotton are soft, breathable and comfortable, but absorb moisture and dry slowly. Synthetic fibers like polyester and nylon are strong, quick-drying and hold their shape, but need finishing to feel soft and manage odour. Elastane is added in small percentages for stretch and recovery.

Within cotton, fiber length, or staple length, is one of the biggest quality factors. Longer staples spin into smoother, stronger yarns with fewer loose ends, which means less pilling and a softer face.

Yarn count: how fine is the yarn?

Yarn count tells you how thick or fine a yarn is. Different fibers use different systems, which is where confusion often starts:

• Ne (English count): used for cotton. It's an indirect system, so a higher number means a finer yarn. 30s is finer than 20s, and 40s finer again.
• Denier: used for synthetic filaments. It's a direct system, so a higher number means a thicker yarn. 75D is finer than 150D.
• Tex: a direct system used internationally, measuring the weight in grams of 1,000 metres of yarn.

For synthetic yarns, the filament count matters too. A 75D/72F yarn has 72 filaments, finer and softer than a 75D/36F yarn of the same thickness.

“Two jerseys at the same GSM can feel completely different. Usually the reason is in the yarn.”

Spinning methods

How cotton is spun changes the yarn's structure, and that changes how the fabric looks and wears.

Ring spinning

Ring-spun yarn is twisted continuously, producing a strong, smooth and soft yarn. It's the standard for premium tees and polos. Combed ring-spun cotton has been combed to remove short fibers first, giving an even smoother, cleaner yarn.

Open-end spinning

Open-end, or rotor, spinning is faster and cheaper. The yarn is bulkier and slightly rougher, which suits heavier fleece and basic garments where cost matters more than softness.

Compact spinning

Compact spinning is a refinement of ring spinning that reduces hairiness. The result is a very clean, strong yarn with excellent pilling resistance, used for high-end knits.

How yarn choices show up in the garment

• Softness: finer counts, longer staples and combed or compact yarns feel softer.
• Pilling: loose short fibers cause pilling. Combed and compact yarns resist it best.
• Strength: ring-spun and compact yarns are stronger than open-end at the same count.
• Print quality: smoother yarns give a cleaner surface for screen printing.
• Cost: finer counts and premium spinning methods cost more per kilo.

What to include in your fabric spec

• Fiber composition with percentages.
• Yarn count in the right system for the fiber, for example 30s Ne or 75D/72F.
• Spinning method for cotton: combed ring-spun, compact or open-end.
• Target GSM and knit structure.
• Any pilling or strength requirements.