What does Ring Spun Denim mean?
Traditionally used in denim up until the late 1970s, ring spun denim was later replaced by more inexpensive Open End yarns. Ring-spun yarn creates unique surface characteristics in the fabric, such as unevenness, giving jeans an irregular authentic vintage look. Greater strength and softness is also achieved.
Heddels explains Ring Spun Denim
Ring-spun yarn is created by continuously rolling and thinning fibers into shape. It takes five times longer to create than open end yarn; however, it produces a much softer and stronger yarn. Ring-spun yarn is also thought to have more character as it is more uneven and contain slubs (thicker areas along the yarn).
Ring-spun denim uses this type of yarn for the warp threads. It has a more uneven feel and texture and is considered more valuable than open end denim; however, the difference in appearance only really begins to show after several months of wear and fade.
Ring-spun denim will have a more unique look to it, with vertical falling (tate-ochi) and a more uneven texture, while open end denim will be more uniform.
Up-close view of ring spun denim: