Abstract
The colour difference of reactive dyed fabrics with several soaping agents and the colour change of them after washing were investigated by means of L*, a*, b* uniform colour scale, from the viewpoint of Fluorescent Brightning Agents (FBA) effect. In conclusion, little colour difference was observed between dyed fabrics in the case of soaping by nonionic surfactant, higher alcoholic neutral detergent or soap and the blank soaped ones, while with sodium carbonate it was observed fairly well in the range of medium to some extent deep depth. FBA built detergent induced the colour change of light colour fabrics. In this paper, I proposed the quantitative method and the criterions using the critical lightness Lc* and the constant K in order to estimate the effect of FBA built deter-gent on colour change. The Lc* value changed with the hue and the constant K did with the hue or with the washing method during washing. The colour change could not be observed after washing when fabrics were soaped by FBA built detergent.
