An electroplating bath for deposition of a dark chromium layer on a workpiece, the electroplating bath comprising: trivalent chromium ions; carboxylate ions being citrate ions, malate ions or mixtures thereof; at least one pH buffer substance; and a mixture of one or more colouring agents selected from the group of sulphur containing compounds according to Formula with one or more colouring agents selected from the group of sulphur containing compounds according to Formula wherein n, p, q are independently of each other integers from 0 to 4; R 1 represents -H, -OH, -COOH, -CO-OCH 3, -CO-OCH 2 -CH 3, -(-O-CH 2 -CH 2 -) m -OH, -CH(-NH 2)-COOH, -CH(-NH-CH 3)-COOH, -CH(-N(-CH 3) 2)-COOH, -CH(-NH 2)-CO-OCH 3, -CH(-NH 2)-CO-OCH 2 -CH 3, -CH(-NH 2)-CH 2 -OH, -CH(-NH-CH 3)-CH 2 -OH, -CH(-N(-CH 3) 2)-CH 2 -OH, -SO 3 H; m represents an integer from 5 to 15; R 2 represents -H, -OH, -(CH 2 -) p -OH, -(CH 2 -) p -C(-NH 2)=NH, -CH 2 -CH 2 -(-O-CH 2 -CH 2 -) m -OH, -R 5, -(CH 2 -) q -COOH, -(CH 2 -) q -CO-OCH 3, -(CH 2 -) q -CO-OCH 2 -CH 3, -(CH 2 -) q -S-(CH 2 -) 2 -OH, -CS-CH 3, -CS-CH 2 -CH 3, -CS-CH 2 -CH 2 -CH 3, R 1 and R 2 together represent a linear chain structure in order to build one of the following ring structures including the central sulphur atom of Formula R 5 represents -H, -CH 3, -CH 2 -CH 3, -CH 2 -CH 2 -CH 3, -CH 2 -CH 2 -CH 2 -CH 3; R 6, R 7, R 8, R 9 represent independently of each other -H, -NH 2, -SH, -OH, -CH 3, -CH 2 -CH 3, -COOH, -SO 3 H; and wherein R 1 is not H if R 2 is H or R 2 is not H if R 1 is H; or salts, tautomeric forms, betaine structures thereof, and wherein =X represents =O, a free electron pair; R 3 represents -R 5, -CH=CH 2, -CH 2 -CH=CH 2, -CH=CH-CH 3, -CH 2 -CH 2 -CH=CH 2, -CH 2 -CH=CH-CH 3, -CH=CH-CH 2 -CH 3, -C≡CH, -CH 2 -C≡CH, -C≡C-CH 3, -CH 2 -CH 2 -C≡CH, -CH 2 -C≡C-CH 3, -C≡C-CH 2 -CH 3, -C(-NH 2)=NH, R 4 represents -R 5, -OR 5, -(CH 2 -) r -CH(-NH 2)-COOH, -(CH 2 -) r -CH(-NH-CH 3)-COOH, -(CH 2 -)-CH(-N(-CH 3) 2)-COOH, -(CH 2 -) r -CH(-NH 2)-CO-OCH 3, -(CH 2 -) r -CH(-NH 2)-CO-OCH 2 -CH 3; r is an integer from 0 to 4; R 3 and R 4 together represent a linear chain structure in order to build one of the following ring structures including the central sulphur atom of Formula R 10 represents -H, -CH 3, -CH 2 -CH 3, -CH 2 -CH 2 -SO 3 H; or salts, tautomeric forms, betaine structures thereof, and wherein the electroplating bath is free of chloride ions, wherein the electroplating bath further comprises sulphate ions, wherein the concentration of carboxylate ions in the electroplating bath ranges from 5 g/L to 35 g/L, and wherein the concentration of the pH buffer substance in the electroplating bath ranges from 50 g/L to 250 g/L. trivalent chromium ions; carboxylate ions being citrate ions, malate ions or mixtures thereof; at least one pH buffer substance; and a mixture of one or more colouring agents selected from the group of sulphur containing compounds according to Formula with one or more colouring agents selected from the group of sulphur containing compounds according to Formula n, p, q are independently of each other integers from 0 to 4; R 1 represents -H, -OH, -COOH, -CO-OCH 3, -CO-OCH 2 -CH 3, -(-O-CH 2 -CH 2 -) m -OH, -CH(-NH 2)-COOH, -CH(-NH-CH 3)-COOH, -CH(-N(-CH 3) 2)-COOH, -CH(-NH 2)-CO-OCH 3, -CH(-NH 2)-CO-OCH 2 -CH 3, -CH(-NH 2)-CH 2 -OH, -CH(-NH-CH 3)-CH 2 -OH, -CH(-N(-CH 3) 2)-CH 2 -OH, -SO 3 H; m represents an integer from 5 to 15; R 2 represents -H, -OH, -(CH 2 -) p -OH, -(CH 2 -) p -C(-NH 2)=NH, -CH 2 -CH 2 -(-O-CH 2 -CH 2 -) m -OH, -R 5, -(CH 2 -) q -COOH, -(CH 2 -) q -CO-OCH 3, -(CH 2 -) q -CO-OCH 2 -CH 3, -(CH 2 -) q -S-(CH 2 -) 2 -OH, -CS-CH 3, -CS-CH 2 -CH 3, -CS-CH 2 -CH 2 -CH 3, R 5 represents -H, -CH 3, -CH 2 -CH 3, -CH 2 -CH 2 -CH 3, -CH 2 -CH 2 -CH 2 -CH 3; R 6, R 7, R 8, R 9 represent independently of each other -H, -NH 2, -SH, -OH, -CH 3, -CH 2 -CH 3, -COOH, -SO 3 H; and wherein R 1 is not H if R 2 is H or R 2 is not H if R 1 is H; =X represents =O, a free electron pair; R 3 represents -R 5, -CH=CH 2, -CH 2 -CH=CH 2, -CH=CH-CH 3, -CH 2 -CH 2 -CH=CH 2, -CH 2 -CH=CH-CH 3, -CH=CH-CH 2 -CH 3, -C≡CH, -CH 2 -C≡CH, -C≡C-CH 3, -CH 2 -CH 2 -C≡CH, -CH 2 -C≡C-CH 3, -C≡C-CH 2 -CH 3, -C(-NH 2)=NH, R 4 represents -R 5, -OR 5, -(CH 2 -) r -CH(-NH 2)-COOH, -(CH 2 -) r -CH(-NH-CH 3)-COOH, -(CH 2 -)-CH(-N(-CH 3) 2)-COOH, -(CH 2 -) r -CH(-NH 2)-CO-OCH 3, -(CH 2 -) r -CH(-NH 2)-CO-OCH 2 -CH 3; r is an integer from 0 to 4; R 3 and R 4 together represent a linear chain structure in order to build one of the following ring structures including the central sulphur atom of Formula R 10 represents -H, -CH 3, -CH 2 -CH 3, -CH 2 -CH 2 -SO 3 H; or salts, tautomeric forms, betaine structures thereof, and wherein the electroplating bath is free of chloride ions, wherein the electroplating bath further comprises sulphate ions, wherein the concentration of carboxylate ions in the electroplating bath ranges from 5 g/L to 35 g/L, and wherein the concentration of the pH buffer substance in the electroplating bath ranges from 50 g/L to 250 g/L.