bark The collected mangrove bark was dried in sunlight and latercrushed to small pieces before being used for dye extraction. The dye extraction was performed by mixing the plant material and dis-tilled water in the weight ratio of 1:10 and boiling for 1 h. After that,the resulting solution was filtered to remove the residue and thedye solution was separated into two portions: (a) one for evaporat-ing under reduced pressure with a rotary evaporator, and (b) onefor dyeing. The crude dye extract obtained from the rotary evapora-tor was dried and then stored in a desiccator before use. To obtain astandard calibration curve, the crude dye extract was later groundand diluted with distilled water. The dilution of the mangrove barkextract showed a relatively clear solution with a linear depen-dence on the concentration–absorbance relation at an absorptionpeak (max) of 278 nm. The concentration of 15 g L−1was calcu-lated from a standard curve of concentrations of the mangrove barkextract dye solution versus absorbance at the wavelength men-tioned.