leno

A leno is a weave structure in which paired warp yarns twist around each weft yarn before and after it passes through, creating a gauze-like fabric with deliberate openness. The twist locks the weft firmly in place even though the fabric is light and airy. This distinguishes leno from plain weave, where warp yarns simply pass over and under the weft without rotation. Leno fabrics are typically made from cotton, linen, or manufactured fibres and range from sheer curtain material to heavier industrial cloth.

The mechanism depends on a leno harness or open reed attachment on the loom. Half the warp ends pass through the reed normally; the other half pass through a separate grating that causes them to shift sideways by half a reed dent. As the reed oscillates during weaving, the two groups of warp yarns cross over and under each other around each entering weft pick. This crossing is what prevents the loose weft yarns from slipping sideways, a serious weakness in plain gauze.

Common variants and applications

Leno appears in many forms. Simple leno uses one cross per weft. Marquesette leno uses multiple twisted pairs for a denser open pattern. Open leno, used for curtains and decorative fabrics, maintains wide spaces between warps. Stronger industrial versions, such as those used in bags or sacks, have closer twists and heavier yarns. Leno is also common in apparel linings and in technical textiles where controlled porosity matters more than opacity.

The name comes from the French "linon", referring to linen fabric, though modern leno is made in all fibres. The weave appeared in European textile production by the 17th century and became standard for high-quality sheer curtaining because it resists sagging and distortion better than plain gauze. Leno looms require more complex mechanics than basic shuttle looms, which limited production historically, but modern rapier and air-jet looms handle leno readily at industrial speeds.

Common faults in leno weaving include crossed warp ends that fail to reverse direction properly, creating slubs or dense spots; weft skew when the twist is uneven along the wale; and harness wear that causes progressive loss of the crossing action. Tension must be carefully controlled because loose warps will not twist cleanly, while tight warps cause excessive friction and weft breakage.