Denim is the most used fabric to manufacture jeans trousers. The most popular color is the non-regular blue, like that in the picture, although there is a lot of production also in other colours. Finishing treatments can change the appearance of the fabric as in stonewashed or faded. It is also used for shirts, vests, jackets, regarding the “juvenile” or casual clothing, but also for classic items. In ancient times it was made of a linen warp and a cotton weft, whereas nowadays it is entirely made of cotton. Its features are robustness and strength (of the material used) together with a certain adaptability (of the twill weave). Denim is very similar to fustian, which is its ancestor. The difference between them is the color of the warp: warp and weft of the fustian are the same color, whereas in denim the weft texture is white or off-white and the warp is blue.