Cobalt blue
Cobalt blue in impure forms had long been used in Chinese porcelain, but it was independently discovered as a pure alumina-based pigment by Louis Jacques Thénard in 1802. Commercial production began in France in 1807. The first recorded use of "cobalt blue" as a color name in English was in 1777. The leading world manufacturer of cobalt blue in the 19th century was Benjamin Wegner's Norwegian company Blaafarveværket ("blue colour works" in Dano-Norwegian). Germany was also famous for production, especially the blue colour works ("Blaufarbenwerke") in the Ore Mountains of Saxony.
Jingdezhen porcelain
The blue pigment was derived from cobalt oxide, which had been imported sporadically from Persia in earlier periods. From the 14th century regular imports of the pigment were obtained from Persia. The cobalt was ground and mixed with a medium, then painted onto the dried bodies of the pots, which were then glazed and fired. At a later date a source of cobalt was found within China; this differed from the Persian ore in the proportion of associated manganese. The colour on the fired pots was a grey-blue rather than a pure blue. By mixing three parts Persian ore to two parts Chinese a rich and soft blue was produced, which became labelled as 'Sumatran' or 'Muhammadan' blue.