Abstract: Cotton fabrics with different color were washed by reference liquid detergents appended with fluorescent brightening agent of separate kinds and concentrations.The effects of fluorescent brightening agent on different color fabrics were shown by comparison analysis of L^*,a^*,b^*,C^*,reflectance curves and the results of visual evaluation.The results showed that the impacts of fluorescent brightening agent are that the whitened fabric becomes whiter,the bleaching fabric and off-white color fabric become brighter and whiter obviously,the light blue and pink fabrics become brighter,grayish and flavescent cotton fabrics also become whiter or lighter.The fluorescent brightening agent makes khaki cotton fabric whiter obviously.The fluorescent brightening agent has no obvious effect on deep color cotton fabrics such as brilliant scarlet,mazarine and black.

Key words: fluorescent brightening agent, liquid detergent, washing, color change