Twill is a type of textile weave with a pattern of diagonal parallel ribs. This is done by passing the weft thread over one or more warp threads then under two or more warp threads and so on, with a “step,” or offset, between rows to create the characteristic diagonal pattern. Because of this structure, twill generally drapes well.
Right-hand twill is the most common method of weaving denim. It is easily recognizable when looking at the back side of the fabric. Right-hand twill, or “Z-twill”, has a compliment and smoother surface than alternate sorts of twill. One separating trademark is how much more tightly and minimal the RHT is expected to be woven with S-bend yarn; which is spun counterclockwise and makes progressively characterized blurs. However, a very common problem with right-hand twill was and still is the twisted leg. Twisted leg occurs especially with non-sanforised denim when the denim is worn and washed. The fabric shrinks and turns in the direction of the weave leaving the side seams in the middle of the leg. the fabric has a special look to it but also it feels softer and more comfortable than normal right-hand twill denim.
Left Hand Twill
Left Hand Twill is woven in an exactly opposite direction of right-hand twill. A style of weaving where the lines of grain run from the top-left hand corner of the fabric towards the bottom-right-hand-corner. Denim jeans that use the left-hand twill have a generally soft and fluffy feeling, especially after washing them. Also known as an ‘S Twill.’
As of the last of the three twills, when you combine RHT with LFT, you get the memorable broken twill. Compared to Left Hand Twill and Right Hand Twill, broken twill is when the diagonal weave of the twill is intentionally reversed at every two warp ends to form a random design. As a result, the natural torque characteristic of regular twill weaves is reduced, eliminating the leg twist effect.