A composition containing (A) an alkali-soluble binder and (B) an azo dye of formula (1), wherein D is the radical of a diazo component of the benzene, naphthalene, diphenyl, azobenzene, thiophene, benzothiazole, benzisothiazole, thiadiazole, indazole, benzotriazole, pyrazole, anthraquinone, naphtholic acid imide, chromone, phthalimide or diphenylene oxide series, X and Y are each independently of the other C2-C6alkylene, n is a number from 1 to 10, Z denotes oxygen or sulphur, and R1 is —X[—O—Y]n-ZH, wherein X, Y, Z and n are as defined above, C1-C12alkyl which may be unsubstituted or substituted by one or more halogen atoms, hydroxy groups, amino groups or C1-C8alkoxy groups, C5-C24aryl which may be unsubstituted or substituted by one or more halogen atoms, hydroxy groups, amino groups, C1-C12alkyl groups or C1-C8alkoxy groups, C6-C30aralkyl which may be unsubstituted or substituted by one or more halogen atoms, hydroxy groups, amino groups, C1-C12alkyl groups or C1-C8alkoxy groups, or a C5-C24cycloaliphatic group which may be unsubstituted or substituted by one or more halogen atoms, hydroxy groups, amino groups, C1-C12alkyl groups or C1-C8alkoxy groups, is useful for the production of colour filters for liquid crystal displays, flat-panel displays, colour image pickup tubes, colour-copying machines etc.