Resinous or cellulose derivative compositions, rubber and other materials of natural or synthetic origin are protected from the deleterious action of ultra-violet light by the incorporation of a light screening agent comprising a hydroxyketone of the formula R2COR1, in which R1 is a phenyl radical which contains a hydroxyl group in ortho-position to the CO group and which may contain further substituents and R2 is a 1 : 11-diphenyl radical bound in the 4-position to the CO group. Specified cellulose derivatives include acetyl cellulose, cellulose triacetate, cellulose propionate, cellulose acetate butyrate, cellulose acetate propionate and nitrocellulose. Example 8 describes the incorporation of 2 : 4-dihydroxy-41-phenyl benzophenone into an acetyl cellulose foil. Specified condensation polymers include polyamides, polyesters, epoxy resins, alkyd resins, olefinic polysulphides and condensation products of formaldehyde with phenol, urea and melamine.  Example 9 describes the treatment of a paper pulp in a bath containing a melamine-formaldehyde condensate and 2 : 4-dihydroxy- 5-N : N1- dimethylaminomethyl-41-phenylbenzophenone in aqueous ethanol, and formation of a laminate by pressing the resulting paper on a tissue paper-melamine resin support.  Example 11 describes the coating of tin-foil with an alkyd melamine stoving varnish comprising an alkyd resin modified with coconut fatty acid, toluene, a melamine-formaldehyde condensate partially etherified with butanol, copper phthalocyanine tetramethoxypropyl sulphonamide and the benzophenone used in Example 9.  Other resinous polymerization products include polyacrylonitrile, acrylic acid resins, vinyl acetate, polyvinyl chloride, copolymers of vinyl chloride and vinylidene chloride, alkyl lacquers, polyethylene, polystyrene, polychloroprene, polybutadiene, and copolymers of butadiene-styrene and of butadiene-acrylonitrile. Example 10 describes the coating of a paper with a composition comprising polyvinyl acetate, an emulsifier, water and 2 : 4-dihydroxy-41-phenylbenzophenone-5-sulphonic acid. Example 12 describes the coating of tin-foil with a film prepared from stabilized polyvinyl chloride, dioctyl phthalate in methyl ethyl ketone and toluene, and copper phthalocyamine tetramethoxy propyl sulphonamide and 2, 4-dihydroxy-41-phenylbenzophenone in acetone. Example 13 describes a foil prepared from polyvinyl chloride, dioctylphthalate, an azo dyestuff and 2-hydroxy-4-ethoxy-41-phenylbenzophenone.  Natural rubber-like materials that may be screened include rubber, balata and gutta percha.ALSO:The invention comprises hydroxyketones of the general formula:  <FORM:0868333/IV (b)/1> in which R1 is a phenyl radical containing a hydroxyl group in ortho-position to the -CO-group and which may contain further substituents.  R2 is a 1:11-diphenyl radical attached through the 4-position, together with processes for their preparation (a) by reacting a compound of the benzene series containing at least one -OH group which may be etherified, with a 1:11-diphenyl-4-monocarboxylic acid halide in the presence of a Friedal-Crafts catalyst, or with a 1:11-diphenyl-4-monocarboxylic acid in the presence of a boron-fluorine compound, particularly BF3; (b) by esterifying a hydroxy compound of the benzene series with a 1:11-diphenyl-4-monocarboxylic halide and subjecting the ester obtained to rearrangement with a Friedal-Crafts catalyst, preferably aluminium chloride.  The products may be subsequently sulphonated and the sulphonic acid converted to a sulphonamide with ammonia or a primary or secondary amine, or subjected to a Mannich reaction to introduce a tertiary aminomethyl group e.g. the piperidino-, morpholino-, diethylamino- or dimethylaminomethyl radical.  The diphenyl moiety may be substituted, e.g. by free or etherified hydroxyl, alkyl and hydroxyalkyloxy groups containing up to 3 carbon atoms; the benzene moiety may contain additional hydroxyl groups, free or etherified, hydroxyalkyloxy, alkyl of up to 3 carbon atoms and kalo radicals.  In Examples:- (1) 1,3-dihydroxybenzene, 1,11-diphenyl-4-carboxylic acid in tetrachlorethane treated with BF3 yield 2,4-dihydroxy-4-dihydroxy-41-phenylbenzophenone; 1,3-dihydroxybenzene is replaced by 2-hydroxy-5,6,7,8-tetrahydronaphthalene, giving the corresponding diphenyl 2-hydroxy-,5,6,7,8-tetrahydronaphyl (3) ketone; (2) 1:11-diphenyl-4-carboxylic acid is treated with thionyl chloride, then with 1,3-dihydroxybenzene in nitrobenzene giving the product of (1) ; (3) the acid chloride is reacted with 1,3-dimethoxybenzene giving 2-hydroxy-41-phenylbenzophenone; the 4-ethoxy analogue is similarly prepared; (4) 1-hydroxy-4-methylbenzene and 1,11-diphenyl-4-carboxylic chloride are added to AlCl3 in trichlorobenzene at 100 DEG C. giving 2-hydroxy-4- methyl-41- phenylbenzophenone, and similarly the 4-chloro and 4-phenyl analogues; (5) para cresyl diphenyl-4-carboxylic acid ester similarly gives 2-hydroxy-4-methyl-41-phenylbenzophenone; (6) 2,4-dihydroxy-41-phenylbenzophenone, trioxy-methylene and dimethylamine hydrochloride yield the corresponding 5-N:N1-dimethylaminoethyl compound; morpholine gives the 5-morpholinomethyl analogue; (7) 2,4-dihydroxy-41-phenyl benzophenone-5-sulphonic acid sodium salt is prepared by direct sulphonation of the hydroxyketone.  p-Cresyl diphenyl-4-carboxylate is prepared by esterification of 1-hydroxy-4-methylbenzene with 1 : 11-diphenyl-4-carboxylic acid chloride in pyridine.ALSO:Textiles and other fibrous materials are prevented from deterioration due to the action of ultra-violet light by the incorporation of a light-screening agent comprising a hydroxyketone of the formula R1COR2, in which R1 represents a phenyl radical containing a hydroxyl group in ortho-position to the CO group, and which may contain further substituents, and R2 represents a 1 : 11-diphenyl radical bound in the 4-position to the CO group.  The textiles may be in the form of fibres, threads, yarns, or felt and may be of animal, vegetable or synthetic origin.  The light-screening agent may be incorporated by a fixing process resembling a dyeing process.ALSO:Varnishes, natural resins, floor polishes, wood stains and furniture polishes (particularly those applicable to light coloured or bleached wood) are protected from the deleterious action of ultra-violet light by the incorporation of a light screening agent comprising a hydroxy ketone of general formula:-R2COR1, in which R1 represents a phenyl radical which contains a hydroxyl group in ortho position to the CO group, and which may contain further substituents, and R2 represents a 1:11-diphenyl radical bound in the 4-position to the CO group.  Candles and soaps are likewise screened from the action of ultra violet light by the incorporation of the above specified hydroxy ketones.ALSO:Cosmetic preparations, e.g. perfumes, soaps, bath salts, hair sprays, skin and face creams, powders, insect repellants and more particularly anti-sunburn oils and creams, contain as lightscreening agent one or more hydroxy ketones of the general formula R1COR2, in which R1 is a phenyl radical which contains a hydroxyl group in ortho-position to the -CO- group and which may contain further substituents, and R2 represents a 1 : 11-diphenyl radical bound in the 4-position to the -CO- group. Examples 14 to 18 detail specific lotions, creams and an aerosol spray all containing 2,4-dihydroxy-41-phenyl benzophenone as the active ingredient, together with inter alia adipic acid, isopropyl tetrahydrofurfuryl ester, glycerol monostearate, benzoic diethylamide, phthalic acid dimethyl ester, groundnut oil, paraffin oil, cetyl alcohol, sodium cetyl sulphate, stearic acid, glycerol, white petroleum jelly, beeswax, lanolin, coconut butter, sodium benzoate ethanol, and trichloro monofluoro- and dichlorodifluoro-methane.  The hydroxyketones specified above can be used as light screening agents to protect edible oils and fats, particularly butter, from deterioration due to ultra-violet light.