1. What is Twill?
Twill fabric refers to textiles where warp and weft threads interlace to form diagonal lines, typically using a 3/1 twill weave. This means each weft thread interlaces with three warp threads before passing under the fourth. Warp threads occupy about two-thirds of the fabric surface, while weft threads are hidden on the back.
2. How to Distinguish Between Left-Hand and Right-Hand Twill?
Right-hand twill (also known as Z-Twill): Extends from the bottom left to the top right, with a grain direction similar to the middle part of the letter "Z," hence also called "Z-twill."
Left-hand twill (also known as S-Twill): Extends from the bottom right to the top left, with a grain direction similar to the middle part of the letter "S," also called "S-twill."
3. Characteristics of Left-Hand and Right-Hand Twill
The reason for the difference in hand feel lies in yarn twist. Most cotton yarns use Z-twist (clockwise twisting). The weaving direction of right-hand twill aligns with the Z-twist direction of the yarn, further tightening the yarn twist during weaving, making the fabric stiffer. The weaving direction of left-hand twill is opposite to the Z-twist, slightly relaxing the yarn twist during weaving, resulting in a naturally softer and fluffier fabric.
4. Leg Twist
After raw denim jeans are washed, the side seams of the legs twist to one side. This is known as leg twist, a natural characteristic of twill fabrics. Leg twist can be prevented through pre-shrinking processes and skew correction treatments.
Wrangler invented Broken Twill, which alternates the weaving patterns of right-hand and left-hand twills. The weft yarn alternates left and right every two warp yarns, forming a herringbone-like pattern.