Coloured Denim is a fabric that is made from tightly woven twill that is wrapped and the weft passes under the warp threads. In the making of coloured Denim fabric, the Yarns are pushed to make strong twists.
One side of the textile is always dominated by blue warp threads while the other side is dominated by white weft threads. This is why the jeans are blue on one side and white or coloured on the other.