Method of achieving a permanent “stone-wash” effect on textile fibre materials

A method of achieving a permanent stone-wash effect on a denim fabric prepared by interweaving a cotton warp yarn and a natural white cotton weft yarn fibre material, in which the cotton warp yarn is impregnated with a naphtholate during a sizing treatment and then interwoven with the natural white cotton weft yarn, a colour is then developed on the fabric with the addition of a diazo salt, the dyed fabric is made up and the made up article is then after-treated with a stone-wash finish.