Denim is a coarse twilled cotton cloth used for jeans, overalls and work uniforms. The twilled weaving produces a diagonal ribbing that distinguishes denim from other cotton.
In denim, the warp threads are dyed indigo, and the weft threads remain white. The result of this twill weaving is that one side of the textile shows the blue warp threads while the other side shows the white threads, which is the reason why most blue jeans or denim shirts are white on the inside. Coloring the fabric with indigo dye creates denim’s fading characteristics, which is considered desirable by many people. Fading usually occurs on the parts of the denim that receive the most stress.