Denim fabrics are also known as blue jeans. Denim fabrics are generally produced from yarns such as polyester, cotton, viscose, nylon lycra. The most prominent feature of denim fabric (jean fabric); warp yarn is dyed in blue indigo dyed and weft undyed (raw) white color. Denim fabrics are usually navy blue, black, blue and so on in 3/1 or 2/1 warp twill weave. warp and white weft threads.