A poly-4-amino-1.2.4-triazole is incorporated in a composition comprising a filament- or film-forming polymer which has little affinity for acid wool dyes, so as to render the composition capable of being dyed with such dyes. The composition may be dyed in the form of flakes, or a precipitated fibrous mass, or in the form of shaped filaments or films. Preferably, the poly-amino-triazole is incorporated in the presence of solvents. The filament- or filmforming polymer may be polyvinyl chlorideacetate, or a cellulose derivative, or polyamide, e.g. cellulose acetate, butyrate or stearate, or a cellulose mixed ester, or ethyl, oxyethyl, or benzyl cellulose ether, or poly-hexamethylene adipamide. The poly-amino-triazole may be made from a dihydrazide of a dicarboxylic acid and an excess of hydrazine, from a dicarboxylic ester and hydrazine, from a dicarboxylic acid or anhydride and hydrazine, or in other ways described in Specifications 612,609 and 613,020. If a solution containing the filament- or filmforming polymer and the poly-amino-triazole is coagulated by a medium having a strong coagulating action, the resulting article or composition may in general be dyed directly from an aqueous bath with an acid wool dye. In the case of dry spun products or of wet spun products in which a weak coagulating bath has been used, the affinity for acid wool dyes is masked, but may be rendered active by treating the filaments, films, or other products with a swelling agent, and in the case of cellulose acetate or other saponifiable materials, the swelling treatment may be preceded by treatment with dilute caustic soda or other mild saponifying agent. The triazole compound and the cellulose derivative or synthetic resin may be dissolved in a common solvent and the solution may be formed directly into filaments or films. Mixtures of chlorinated hydrocarbons and alcohols may be used for this purpose. The two ingredients may be dissolved in a common solvent such as formic or acetic acid, then precipitated by addition of water, and then dispersed in a dry-spinning solvent such as acetone. The proportion of polyaminotriazole may be 5-20 per cent based on the total weight of this ingredient and the filament-or film-forming substance. Compositions containing polyamides may be melt spun to form filaments. The polyamino-triazole may or may not be of such a high molecular weight as to be filament-forming per se. In an example, a solution in acetic acid of cellulose acetate and a polyaminotriazole, made from sebacic dihydrazide and hydrazine hydrate, is precipitated as a white fibrous mass by pouring into cold water, and the mass is washed and dried. It can then be dyed with wool dyes, e.g. Naphthalene Scarlet BS, from an aqueous solution at 80 DEG C., the bath preferably containing a trace of acetic acid. In another example, hanks of yarn made from cellulose acetate containing a polyaminotriazole are placed in a dyebath containing an acid wool dye and a mixture of water, methyl alcohol and acetic acid, the temperature of the bath being 70 DEG C. In another example, a solution of a polyaminotriazole in formic acid is mixed with a formic acid solution of a polyamide, made by melt polymerization of adipic acid and hexamethylene diamine using hexamethylene diamine as viscosity stabilizer. The mixture is poured into cold water, the fibrous mass obtained is dried and melted, and the molten material is extruded to form filaments. Hanks of the yarn obtained are dyed at 80 DEG C. in an aqueous bath containing Kiton Yellow S and a trace of acetic acid. Specification 613,986 also is referred to.ALSO:A poly-4-amino-1,2,4-triazole is incorporated in a composition comprising a filament or film-forming polymer which has little affinity for acid wool dyes, so as to render the composition capable of being dyed with such dyes. The composition may be dyed in the form of flakes, or a precipitated fibrous mass, or in the form of shaped filaments or films. Preferably, the poly-amino-triazole is incorporated in the presence of solvents. The filament- or film-forming polymer may be polyvinyl chloride-acetate, or a cellulose derivative, or polyamide, e.g. cellulose acetate, butyrate or stearate, or a cellulose mixed ester, or ethyl oxyethyl, or benzyl cellulose ether, or poly-hexamethylene adipamide. If a solution containing the filament- or film-forming polymer and the polyamino-triazole is coagulated by a medium having a strong coagulating action, the resulting article or composition may in general be dyed directly from an aqueous bath with an acid wool dye. In the case of dry spun products or of wet spun products in which a weak coagulating bath has been used, the affinity for acid wool dyes is masked but may be rendered active by treating the filaments, films, or other products with a swelling agent, and in the case of cellulose acetate or other saponifiable materials, the swelling treatment may be preceded by treatment with dilute caustic soda or other mild saponifying agent. In an example, a solution in acetic acid of cellulose acetate and a polyaminotriazole, made from sebacic dihydrazide and hydrazine hydrate, is precipitated as a white fibrous mass by pouring into cold water, and the mass is washed and dried. It can then be dyed with wool dyes, e.g. Naphthalene Scarlet BS, from an aqueous solution at 80 DEG C., the bath preferably containing a trace of acetic acid. In another example, hanks of yarn made from cellulose acetate containing a polyaminotriazole are placed in a dyebath containing an acid wool dye and a mixture of water, methyl alcohol, and acetic acid, the temperature of the bath being 70 DEG C. In another example, a solution of a polyaminotriazole in formic acid is mixed with a formic acid solution of a polyamide, made by melt polymerization of adipic acid and hexamethylene diamine using hexamethylene diamine as viscosity stabilizer. The mixture is poured into cold water, the fibrous mass obtained is dried and melted, and the molten material is extruded to form filaments. Hanks of the yarn obtained are dyed at 80 DEG C. in an aqueous bath containing Kiton Yellow S and a trace of acetic acid. Specification 613,986, [Group IV (a)], also is referred to.