Cobalt Blue

Cobalt Blue was invented by French chemist Louis Jacques Thénard in 1802. He sintered cobalt oxide with aluminum oxide at high temperatures in an experiment, obtaining a pure, clear, perfect blue pigment that was neither purplish nor greenish. This invention was promptly marketed as 'Thénard's Blue.'

Cobalt Blue appeared just in time to fill the void left by the expensive Ultramarine. It was brighter than Ultramarine and much cheaper. The Impressionist painters quickly embraced this new pigment. Renoir and Monet used Cobalt Blue to depict the sky and water reflections on the Seine River near Paris.

Cobalt Blue also brought revolutionary breakthroughs in ceramics. Although cobalt had been used in Chinese Yuan and Ming blue-and-white porcelain, European cobalt blue glaze reached its peak in the 18th century at the Sèvres and Copenhagen porcelain factories. The Royal Copenhagen 'Blue Fluted' series, hand-painted with Cobalt Blue on white porcelain, became a Danish national treasure-level craft.

In the 19th century, Cobalt Blue proved to be an extremely stable pigment, resistant to light, heat, acids, and alkalis. This property led to its use not just in painting but as a coating. British and French railway systems procured Cobalt Blue extensively to paint train carriages and station signage.

In modern industry, Cobalt Blue's uses are vast. From plastic coloring to concrete staining, from cosmetics to contact lenses, Cobalt Blue is ubiquitous. Its bright, clear blue, unchanged for over a century, is a successful example of the marriage between technology and aesthetics.