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.
Powder blue
Although smalt itself is a deep, dark blue hue, powder blue is nowadays depicted as more of a pale cobalt blue as illustrated by the examples below, which show powder blue as defined by British and Australian Standards for paint colours along with an example of one manufacturer's actual Powder Blue paint, and a consensus definition produced by an online colour names survey in which 140,000 people took part. It can be seen that although the sources differ on how pale or saturated a colour "powder blue" is, they broadly agree as to its hue.