Monoazo pigments, fast to light, which are metal complexes containing two atoms of metal per two molecules of monoazo compound, are obtained by coupling a diazotised arylamine free from carboxylic and sulphonic acid groups and carrying no hydroxy group in o-position to the sole diazotisable amino group, with 2 : 3-hydroxynaphthoic acid or a substitution product thereof in which the substituent is halogen, nitro, alkyl or alkoxy and is on the ring not carrying the hydroxy and carboxylic groups, at least one of the metal atoms being nickel or cobalt and the other being of atomic weight between 54 and 65, e.g. copper, nickel, cobalt, iron or manganese, or an alkaline earth metal, e.g. calcium, strontium or barium. In examples: (1) the monoazo compound, 4-nitroaniline --> (alkaline with sodium hydroxide and sodium carbonate) 2 : 3-hydroxynaphthoic acid is heated for 3 hours with an aqueous ammoniacal solution of nickel chloride at 90 DEG C.; (2) the monoazo compound of (1) produced by coupling in sodium carbonate solution buffered with sodium acetate is similarly metallised with an addition of para soap to the metallising medium; the ammonia may be replaced by sodium hydroxide added gradually during the metallisation; (3) the nickel chloride in (1) is replaced by cobaltous chloride to obtain the cobaltous complex or, by addition of hydrogen peroxide to the metallising medium, the cobaltic complex; (4) the diazo component in (1) is replaced by 3-nitroaniline; (5) the nickel chloride in (1) is partly replaced by barium chloride; (6) an ammoniacal aqueous slurry of the monoazo compound, 2 : 5 - dichloroaniline --> 2 : 3 - hydroxynaphthoic acid containing calcium chloride and nickel chloride is heated for 2 hours at 90 DEG C.; (7) the monoazo compound, aniline --> 2 : 3-hydroxynaphthoic acid is converted as in (1) into the nickel complex; the ammonia in the metallising medium may be replaced by other bases, e.g. di- or tri-ethanolamine, pyridine or morpholine; (8) the monoazo compound, 1-naphthylamine --> 2 : 3-hydroxynaphthoic acid is heated for 3 hours in an aqueous solution at 90 DEG C. containing nickel chloride and aniline, N-b -hydroxyethyl-aniline, N-di-(b -hydroxyethyl)-aniline, urea or ammonia. A table is also given showing the colours of the prints obtainable with the use of nickel or cobalt as the metal, of various additional diazo components and of 2 : 3-hydroxynaphthoic acid as the coupling component, the additional diazo components being 3- or 4-chloroaniline, 2- or 3-nitro-4-chloroaniline, 2-nitro-4-aminotoluene, 2 - amino - 5 - nitrotoluene, 2- or 4 - anisidine, 2-amino-4- or 5-nitroanisole, 4-amino-2-chlorophenetole, 4 - amino - 41 - ethoxydiphenylamine, 2-naphthylamine and 1-aminoanthraquinone. Other diazo components which may be used are 2-, 3- or 4-toluidine, 1 : 3-dimethyl-4-aminobenzene, p-xylidine, 2-chloroaniline, 2-, 3- or 4-bromoaniline, chlorotoluidines, 3-anisidine, 2-, 3- or 4-phenetidine, chloro-anisidines, other chlorophenetidines, nitrochloroanilines, nitroanisidines, dichloroanilines and nitrotoluidines, 2 : 5 - dimethoxyaniline, nitrophenetidines, 3-aminobenzotrifluoride, trichloroanilines, nitrochlorotoluidines, 3- or 4-benzoylaminoaniline, 3- or 4-aminoacetophenone, 3- or 4-aminobenzophenone, 2-, 3- or 4-aminophenyl-alkylsulphones, 4-dodecylaniline, 2-, 3- or 4-aminobenzenesulphondimethylamide, 2-, 3- or 4-cyanoaniline, 2-, 3- or 4-aminoalkylbenzoates, 2-, 3- or 4 - aminodiphenyl ether, 4 - nitro - 41 - amino - diphenyl sulphide, 4-aminodiphenylamine or its 41-ethoxy derivative, 2- or 4-aminodiphenyl, 2-aminobenzthiazole or its 6-ethoxy derivative, 2-amino-4-methylthiazole, 5-, 6- or 8-aminoquinoline and 1 - phenyl - 4 - amino - 5 - chloro - pyrazole. Other specified coupling components are the 6-chloro-, 6-bromo-, 5- or 8-nitro-, p 6-methyl- (cf. Specification 391,987), 6-methoxy-and 6-ethoxy- (cf. Specification 366,140) derivatives of 2 : 3-hydroxynaphthoic acid. The pH value of the metallisation medium is advantageously maintained above 6.5 by addition of a basic compound, specified compounds additional to those in the above examples being propylamine, mono-, di- and tri-methylamine, ethylamine, formamide, acetamide, dimethylformamide, hexylamine, cyclohexylamine, methylglycamine, taurine, b -dimethylaminopropanolsulphonic acid, toluidines, xylidines, naphthylamines, diphenylamine, piperazine, dimethylsulphanilic acid, melamine, pyrrole, indole, carbazole, hexamethyleneimine, hexamethylenetetramine, mono- and di-methylglycine, dimethylolurea, sodium formate, oxalate, citrate, maleate, succinate or chloracetate and potassium glycollate, gluconate or tartrate.