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.
Yellow
The painter Vincent van Gogh was a particular admirer of the color yellow, the color of sunshine. Writing to his sister from the south of France in 1888, he wrote, "Now we are having beautiful warm, windless weather that is very beneficial to me. The sun, a light that for lack of a better word I can only call yellow, bright sulfur yellow, pale lemon gold. How beautiful yellow is!" In Arles, Van Gogh painted sunflowers inside a small house he rented at 2 Place Lamartine, a house painted with a color that Van Gogh described as "buttery yellow." Van Gogh was one of the first artists to use commercially manufactured paints, rather than paints he made himself. He used the traditional yellow ochre, but also chrome yellow, first made in 1809, and cadmium yellow, first made in 1820.