Types of denim include natural, polycore, ring, ring-spun, ring-ring, bull, dual ring spun, black-black, open end, over twisted, printed, reverse and pinto wash. These different types refer to variations in the types of yarn and processes used to construct and dye the fabric.
Ring-spun yarn creates the traditional surface unevenness and vintage look of denim. This type of yarn was used to make denim until the 1970s. Open-end type, introduced in the 1970s, lowered the cost by omitting parts of the spinning process. Premium labels often use dual-ring-spun yarn for a softer, textured feel. Pinto-wash denim is the result of a 1969 flood. It was thought the denim was ruined, but a process to remove the dye gave the fabric a faded, mottled appearance that was an instant success with fashion designers.