Abstract
Denim is one of the most frequently used fabrics for blue jeans. After washing denim fabric frequently changes its size and color. Salespersons recommended that after purchasing blue jeans customers should dry clean them once before washing. The aim of this study was to investigate to what degree washing with a household washing machine and dry cleaning affected the dimensions and the color of denim fabric. The denim fabric shrank greatly after the first laundering in warp direction regardless of whether it had been dry-cleaned or not. However, it shrank little from the second to the tenth laundering and after each number of dry cleanings. The thickness of the denim changed in the same way as the shrinkage occurred when the number of launderings or dry-cleanings increased. Although the indigo came out of the denim into washing liquor, both of the $L^*$ values and the $b^*$ values of the laundered and the dry-cleaned denim fabrics were lower than those of the control fabric. Darkening of the fabric after washing attributed to the shrinkage in warp; specifically the deep-blue warp yarns more spaced on the fabric face and the back. The $L^*$ and $b^*$ values of the dry-cleaned fabric decreased less than those of the laundered. The value of $a^*$ increased much less than the other values. Staining of the white cotton fabric laundered with the denim fabrics became less as the number of launderings increased. The degree of staining from the dry-cleaned denim was much lower than that of the laundered fabric.