Blue-fluorescent effects are imparted to cellulosic materials by incorporating therein a small quantity of a compound of the general formula <FORM:0647718/IV (a)/1> or a salt thereof, in which R and R1 are alkyl, aryl or aralkyl groups, X and X1 are O or a small integer and n, n1, m and m1 are integers. In an example, a regenerated cellulose wrapping sheet is immersed in an aqueous solution containing glycerine and the sodium salt of 4,41-di - p - methoxybenzoylaminostilbene - 2,21 - di-sulphonic acid.ALSO:Blue-fluorescent effects are imparted to cellulosic materials by incorporating therein a small quantity of a compound of the general formula <FORM:0647718/IV (c)/1> or a salt thereof in which R and R1 are alkyl, aryl or aralkyl groups, X and X1 are O or a small integer and n, n1, m and m1 are integers. The process may be applied to the treatment of white cellulosic materials such as cotton, linen and paper for improving the whiteness, and may be carried out by immersing the material in an aqueous solution of the blue-fluorescent compound. A small amount of a coloured substance, e.g. ultramarine, may be incorporated with the blue-fluorescent compound. In examples: (1) regenerated cellulose wrapping sheets are immersed in an aqueous solution containing glycerine and the sodium salt of 4,41 - di - p - methoxybenzoylaminostilbene-2,21-disulphonic acid to give a sheet suitable for wrapping foodstuffs sensitive to light; (2) undyed bleached cotton yarn is treated in an aqueous bath containing sodium sulphate and the blue-fluorescent compound of (1); (3) white cotton cloth is rinsed in an aqueous bath containing the compound of (1); (4) white cotton cloth is washed in a liquor containing a soap powder which itself contains the compound of (1); (5) textile materials are treated with a starch which has been treated by suspending it in a solution containing sodium sulphate and the blue-fluorescent compound of (1); and (6) cotton cloth is treated with an aqueous solution containing the same blue-fluorescent compound and ultramarine. Other blue-fluorescent compounds specified are sodium 4,41 - di - o - methoxybenzoylaminostilbene - 2,21 - disulphonate, sodium 4,41 - di-p - ethoxybenzoylaminostilbene - 2,21 - di-sulphonate, sodium 4,41 - di - 311,411,511 - trimethoxybenzoylaminostilbene - 2,21 - disulphonate, sodium 4,41 - di - p - phenoxybenzoylaminostilbene - 2,21 - disulphonate, sodium 4,41 - di - p - benzyloxybenzoylaminostilbene-2,21 - disulphonate, sodium 4,41 - di - 411-methoxy - 311 - methylbenzoylaminostilbene-2,21 - disulphonate, sodium 4,41 - di - p-methoxybenzoyl - p - aminobenzoylaminostilbene - 2,21 - disulphonate, and sodium 4,41 - di - 311 - acetylamino - 411 - methoxybenzoylaminostilbene - 2,21 - disulphonate. Specifications 596,324, 596,405 and 647,759, [Group IV (b)], are referred to.ALSO:Blue-fluorescent effects are imparted to cellulosic materials by incorporating therein a small quantity of a compound of the general formula <FORM:0647718/III/1> or a salt thereof, in which R and R1 are alkyl, aryl or aralkyl groups, X and X1 are 0 or a small integer and n, n1, m and m1 are integers. In an example, white cotton cloth is washed in a liquor containing a soap powder which itself contains the sodium salt of 4,41-di-p-methoxybenzoylaminostilbene - 2,21 - disulphonic acid. Other blue-fluorescent compounds specified are sodium 4,41 - di - o - methoxybenzoylaminostilbene - 2,21 - disulphonate, sodium 4,41 - di - p - ethoxybenzoylaminostilbene - 2,21 - disulphonate, sodium 4,41 - di - 311,411,511 - trimethoxybenzoylaminostilbene - 2,21 - disulphonate, sodium 4,41 - di - p - phenoxybenzoylaminostilbene - 2,21 - disulphonate, sodium 4,41 - di - p - benzyloxybenzoylaminostilbene - 2,21 - disulphonate, sodium 4, 41-di-411-methoxy-311-methylbenzoylaminostilbene -2,21-disulphonate, sodium 4,41 - di - p - methoxybenzoyl - p - amino - benzoylaminostilbene - 2,21 - disulphonate, and sodium 4,41 - di - 311 - acetylamino - 411 - methoxy-benzoylaminostilbene-2,21-disulphonate.ALSO:Blue-fluorescent effects are imparted to cellulosic materials by incorporating therein a small quantity of a compound of the general formula <FORM:0647718/V/1> or a salt thereof in which R and R1 are alkyl, aryl or aralkyl groups, X and X1 are 0 or a small integer and n, n1, m and m1 are integers. A small amount of a coloured substance, e.g. ultramarine, may be incorporated together with the blue-fluorescent compound. In an example, textile materials are treated with a starch which has been treated by suspending it in a solution containing sodium sulphate and the blue-fluorescent sodium salt of 4,41- di-p-methoxybenzoylaminostilbene - 2,21 - disulphonic acid. Other blue-fluorescent compounds specified are sodium 4,41-di-o-methoxybenzoylaminostilbene - 2,21 - disulphonate, sodium 4,41 - di - p - ethoxybenzoylaminostilbene - 2,21-disulphonate, sodium 4,41 - di - 311,411,511-trimethoxybenzoylaminostilbene - 2,21 - disulphonate, sodium 4,41 - di - p - phenoxybenzoylaminostilbene - 2,21 - disulphonate, sodium 4,41 - di - p -benzyloxybenzoylaminostilbene - 2,21 - disulphonate, sodium 4,41 - di-411 - methoxy - 311 - methylbenzoylaminostilbene - 2,21 - disulphonate, sodium 4,41 - di - p-methoxybenzoyl - p1 - aminobenzoylaminostilbene - 2,21 - disulphonate, and sodium 4,41-di - 311 - acetylamino - 411 - methoxybenzoylaminostilbene-2,21-disulphonate.ALSO:Blue-fluorescent effects are imparted to cellulosic materials by incorporating therein a small quantity of a compound of the general formula <FORM:0647718/VI/1> or a salt thereof in which R and R1 are alkyl, aryl or aralkyl groups, X and X1 are O or a small integer and n, n1, m and m1 are integers. In an example, regenerated cellulose wrapping sheets are immersed in an aqueous solution containing glycerine and the sodium salt of 4. 4\sv-di-p-methoxybenzoylaminostilbene-2, 2\sv-disulphonic acid to give a sheet suitable for wrapping foodstuffs sensitive to light. Other blue-fluorescent compounds specified are sodium 4, 4\sv-di-o-methoxybenzoylaminostilbene-2, 2\sv-disulphonate, sodium 4, 4\sv-di-p-ethoxybenzoylaminostilbene-2, 2\sv-disulphonate, sodium 4, 4\sv-di-3\yF, 4\yF, 5\yF-trimethoxybenzoylaminostilbene-2, 2\sv-disulphonate, sodium 4, 4\sv-di-p-phenoxybenzoylaminostilbene-2, 2\sv-disulphonate, sodium 4 4\sv-di-p-benzyloxybenzoylaminostilbene-2, 2\sv-disulphonate, sodium 4, 4\sv-di-4\yF-methoxy-3\yF-methylbenzoylaminostilbene-2, 2\sv-disulphonate, sodium 4,4\sv-di-p-methoxybenzoyl-p-aminobenzoylaminostilbene-2, 2\sv-disulphonate, and sodium 4,4\sv-di-3\yF-acetylamino-4\yF-methoxybenzoylaminostilbene-2, 2\sv-disulphonate.