Azo dyes, complex metal compounds of.-Metalliferous azo dyestuffs are obtained by treating o-oxyazo dyestuffs free from sulphonic, carboxylic, sulphonamide, or N-substituted sulphonamide groups with a suspension of one or more agents yielding metal other than chromium. Specified agents are the oxides, hydroxides, carbonates, and sulphides of copper, cobalt, nickel, manganese, iron, aluminium, and zinc, and the treatment may be effected with or without the addition of an organic salt or an alkaline, neutral, or acid inorganic salt. The products, being fast to light, are specially suitable for incorporation in varnishes having a basis of cellulose esters or ethers or of natural or artificial resins. The following examples are specified. (1) The dyestuff 4-nitro-2-aminophenol --> resorcinol is boiled under reflux with an aqueous suspension of manganic oxide in excess; the product is separated from the excess of the oxide by extraction with dilute sodium carbonate solution and precipitation with acetic acid; its solution in nitrocellulose varnish gives on metal surfaces vivid brown coatings very fast to light; when the manganic oxide is replaced by ferric oxide, ferroso-ferric oxide (Fe3O4), and nickel oxide (Ni2O3), the products give red, blackish brown, and brown orange varnishes respectively; alumina cobalt oxide (Co2O3), or zinc oxide may also be used, and the metallization may be effected in presence of a neutral salt, such as common salt, or of an alkaline salt, such as sodium carbonate, or of an acid salt, such as ammonium sulphate, to obtain variations of the shade, solubility, etc. (2) The dyestuff 4-chloro-2-aminophenol --> 1-phenyl-3-methyl-5-pyrazolone is boiled under reflux with an aqueous suspension of freshly precipitated ferric hydroxide; the product gives a greenish yellow varnish, fast to light. (3) The dyestuff 4-nitro-2-aminophenol --> resorcinol is boiled under reflux with an aqueous suspension of freshly precipitated nickel hydroxide; the product gives a brownish yellow varnish, fast to light. (4) The dyestuff 4-chloro-2-aminophenol --> b -naphthol is boiled under reflux with a suspension of freshly precipitated ferric hydroxide; the product gives a brownish black nitrocellulose varnish, very fast to light; the corresponding product from the dyestuff 4-nitro-2-aminophenol --> resorcinol similarly gives a brown shade very fast to light. (5) The dyestuff 4-nitro-2-aminophenol --> resorcinol is boiled under reflux with a suspension of freshly precipitated ferric hydroxide in an aqueous solution of sodium sulphate; the product gives a vivid brown nitrocellulose varnish, very fast to light; the sodium sulphate may be replaced by common salt, sodium thiosulphate, sodium acetate, sodium sulphite, primary sodium phosphate, or sodium bisulphite; the precipitation mixture may constitute the suspension of the metal hydroxide in the solution of the salt, thus removing any necessity for separating the precipitate. (6) The dyestuff 4-chloro-2-aminophenol --> b -naphthol is boiled under reflux with a suspension of freshly precipitated ferric hydroxide in an aqueous solution of tertiary sodium phosphate, the product gives a dark brown to black nitrocellulose varnish, very fast to light; the sodium phosphate may be replaced by sodium bicarbonate or sodium acetate; when the ferric hydroxide is replaced by nickel carbonate orange varnishes, fast to light, are obtained; the corresponding product from the dyestuff 4-nitro-2-aminophenol --> resorcinol is brown. (7) The dyestuff 4-chloro-2-aminophenol --> resorcinol is boiled under reflux with an aqueous suspension of freshly precipitated zinc carbonate; the product gives a brownish yellow nitrocellulose varnish. (8) The dyestuff 4-chloro-2-aminophenol --> resorcinol is boiled under reflux with an aqueous suspension of freshly precipitated cobalt sulphide with or without an addition of sodium acetate, sodium carbonate or bicarbonate, primary or tertiary sodium phosphate, or sodium sulphate; the products give red nitrocellulose varnishes. Specifications 1611/15 and 16803/15, [both in Class 2 (iii), Dyes, &c.], are referred to. The Specification as open to inspection under Sect. 91 (3) (a) of the Acts comprises also the production of the metal compounds of o-carboxyazo dyestuffs and their incorporation in varnishes. This subject-matter does not appear in the Specification as accepted.