Abstract: A water soluble disazo colorant represented by formula (I) in the form of free acid: ##STR1## wherein K represents ##STR2## [wherein A represents a methyl group or a carboxylic group; R.sup.2 represents a hydrogen atom, an alkyl group of 1 to 8 carbon atoms, a sulfoalkyl grouop of 1 to 4 carbon atoms, or an alkyl group of 1 to 4 carbon atoms which is substituted by an alkoxy group of 1 to 4 carbon atoms;R.sup.3 represents a hydrogen atom, a halogen atom, a cyano group, a --CONH.sub.2 group, a carboxyl group, a sulfonic group, or a sulfomethyl group, p represents an integer of 1 or 2];Z represents a fluorine atom or ##STR3## [wherein R.sup.4 represents a hydrogen atom or an alkyl group of 1 to 4 carbon atoms;R.sup.5 and R.sup.6 each represents independently a hydrogen atom, an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, a sulfonic group, or a halogen atom; Y represents --SO.sub.2 CH.dbd.CH.sub.2 or --SO.sub.2 CH.sub.2 CH.sub.