Removal of the indigo color by laser beam-denim interaction

Our experiments show that the laser fading process removes efficiently indigo-dye from denim support. We use the beams from Nd:YAG laser (1064nm and its second harmonic 532nm) and CO2 (10.6µm) lasers. Different laser pulse parameters were used in order to obtain laser power density and fluency to start the ablation process. The purpose of this work is to determine the change of denim diffuse reflectivity spectra after laser irradiation with different wavelength and different power density. The change of diffuse reflectivity coefficient was up to 17% at 450nm wavelength (from 8% reflectivity for unirradiated denim).