The invention comprises 1:2:4-Triazine compounds of the general formula: <FORM:0954415/C2/1> in which Z represents a hydrogen or a halogen atom, or a C1-C4 alkyl group; R and R1 are identical and each represents a pyridine residue, a benzene residue of the formula: <FORM:0954415/C2/2> or a benzene residue of the formula: <FORM:0954415/C2/3> in which Y is a hydrogen or halogen atom, hydroxyl group, alkyl or alkoxy group with 1 to 4 carbon atoms. The compounds may be prepared by condensing, at 115 DEG -125 DEG C., 1 mole of a 1:2-diketone of formula: <FORM:0954415/C2/4> with 1 mole of a monocarboxylic acid hydrazide of formula: <FORM:0954415/C2/5> in glacial acetic acid, with addition of ammonium acetate. The compounds are used as light screening agents.ALSO:Compounds used as ultra violet light screening agents have the general formula: <FORM:0954415/C3/1> in which Z represents a hydrogen or a halogen atom, or a C1-C4 alkyl group; R and R1 each represent a pyridine residue, a benzene residue of the formula: <FORM:0954415/C3/2> or a benzene residue of the formula: <FORM:0954415/C3/3> in which Y is a hydrogen or halogen atom, hydroxyl group, alkyl or alkoxy group with 1 to 4 carbon atoms. The compounds may be incorporated in a substratum to protect it, or substances contained in it, e.g. colouring matter or assistants, from attack or it may be used in a filter layer to protect a substratum placed underneath. Materials protected include lacquers and films, e.g. of acetylcellulose, cellulose propionate, cellulose butyrate and mixtures thereof; also nitrocellulose, vinyl acetate polyvinyl chloride, copolymers of vinyl chloride and vinylidene chloride, alkyd lacquers, polyethylene, polyamides, polyacrylonitrile, and polyesters; natural or synthetic resins, e.g. epoxy resins, polyester resins, vinyl resins, polystyrene resins, alkyd resins, phenol-, urea- or melamineformaldehyde resins and emulsions of synthetic resins. In this case the light screening agent is preferably added before or during polymerisation. The compounds may also be used with natural rubber-like materials, e.g. rubber, balata, gutta percha, also polychloroprene, olefinic polysulphides, polybutadiene and acrylonitrile which may also contain fillers, pigments or vulcanisation accelerators. In this case the 1:2:4-Triazines delay the ageing thus preventing changes in plasticity and embrittlement. Examples are given for a film of acetylcellulose, fabrics and filaments of polyamides, and for polyvinyl chloride.ALSO:Compounds used as ultra violet light screening agents have the general formula <FORM:0954415/C3/1> in which Z represents a hydrogen or a halogen atom, or a C1-C4 alkyl group; R and R1 each represent a pyridine residue, a benzene residue of the formula <FORM:0954415/C3/2> or a benzene residue of the formula <FORM:0954415/C3/3> in which Y is a hydrogen or halogen atom, hydroxyl group, alkyl or alkoxy group with 1 to 4 carbon atoms.  The compounds may be incorporated in a substratum to protect it, or substances contained in it, e.g. colouring matter or assistants, from attack or it may be used in a filter layer to protect a substratum placed underneath. Materials protected include hydrophobic substances containing oils, fats or waxes, such as candles, floor polishes, floor stains, wood stains, furniture polishes.ALSO:Compounds used as ultra violet light screening agents have the general formula: <FORM:0954415/C3/1> in which Z represents a hydrogen or a halogen atom, or a C1-C4 alkyl group; R and R1 each represent a pyridine residue, a benzene residue of the formula: <FORM:0954415/C3/2> or a benzene residue of the formula: <FORM:0954415/C3/3> in which Y is a hydrogen or halogen atom, hydroxyl group, alkyl or alkoxy group with 1-4 carbon atoms. The compounds may be incorporated in a substratum to protect it, or substances contained in it, e.g. colouring matter or assistants, from attack or it may be used in a filter layer to protect a substratum placed underneath.  Materials protected include animal furs and leathers made from animal skins by natural or chemical tanning and products made therefrom.ALSO:Compounds used as ultra violet light screening agents have the general formula <FORM:0954415/A5-A6/1> in which Z represents a hydrogen or a halogen atom, or a C1-C4 alkyl group; R and R1 each represent a pyridine residue, a benzene residue of the formula <FORM:0954415/A5-A6/2> or a benzene residue of the formula <FORM:0954415/A5-A6/3> in which Y is a hydrogen or halogen atom, hydroxyl group, alkyl or alkoxy group with 1 to 4 carbon atoms. The compounds may be incorporated in a substratum to protect it, or substances contained in it, e.g. colouring matter or assistants, from attack or it may be used in a filter layer to protect a substratum placed underneath.  Materials protected include cosmetics such as perfumes, dyed or undyed soaps and bath salts, skin and face creams, powders, insect repellents, sunburn oils and creams.ALSO:Compounds used as ultra violet light screening agents have the general formula:-  <FORM:0954415/B1-B2/1> in which Z represents a hydrogen or a halogen atom, or a C1-C4 alkyl group; R and R1 each represent a pyridine residue, a benzene residue of the formula:- <FORM:0954415/B1-B2/2> or a benzene residue of the formula:- <FORM:0954415/B1-B2/3> in which Y is a hydrogen or halogen atom, hydroxyl group, alkyl or alkoxy group with 1-4 carbon atoms.  The compounds may be incorporated in a substratum to protect it, or substances contained in it, e.g. colouring matter or assistants, from attack or it may be used in a filter layer to protect a substratum placed underneath.  Materials protected include paper and textiles wherein the compounds are incorporated in stable coating and dressing agents, e.g. those based on starch, casein, or a synthetic resin.ALSO:Compounds used as ultra violet light screening agents have the general formula:-  <FORM:0954415/D1-D2/1> in which Z represents a hydrogen or a halogen atom, or a C1-C4 alkyl group; R and R1 each represent a pyridine residue, a benzene residue of the formula:- <FORM:0954415/D1-D2/2> or a benzene residue of the formula:- <FORM:0954415/D1-D2/3> in which Y is a hydrogen or halogen atom, hydroxyl group, alkyl or alkoxy group with 1 to 4 carbon atoms.  The compounds may be incorporated in a substratum to protect it, or substances contained in it, e.g. colouring matter or assistants, from attack or it may be used in a filter layer to protect a substratum placed underneath.  Materials protected include feathers and textiles.  The textiles may be in the form of fibres, filaments, yarns, woven or knitted fabrics or as felt.  Materials for the textiles may be wool, silk, cotton, hemp, flax, linen, jute, ramie, or semi-synthetic materials, e.g. rayon, viscoses, or synthetic materials obtained by polymerization.  For semi-synthetic materials the compounds may be incorporated in the spinning composition.  The compounds may also be used to protect paper from ultra-violet light. They may be incorporated in stable coating or dressing agents or, in an example, paper prepared in a hollander from bleached sulphite or sulphate cellulose, zinc sulphide, aluminium sulphate and an azo pigment is immersed in a bath containing a melamine-formaldehyde resin and a compound of the above formula.ALSO:Materials are protected against discolouration and oxidation by ultra-violet light by compounds of formula:-  <FORM:0954415/A1-A3/1> in which Z represents a hydrogen or a halogen atom, or a C1-C4 alkyl group; R and R1 each represent a pyridine residue, a benzene residue of the formula:-  <FORM:0954415/A1-A3/2> or a benzene residue of the formula:-  <FORM:0954415/A1-A3/3> in which Y is a hydrogen or halogen atom, hydroxyl group, alkyl or alkoxy group with 1 to 4 carbon atoms. The compound may be incorporated in a film, foil or dressing for the material. Materials protected include water-repellent preparations containing oils, fats and waxes, wool, silk, feathers, hair, furs, skins, leather and vegetable cellulosic fibres.