Prussian Blue

Prussian Blue was invented by accident around 1704 by the Berlin paint merchant Diesbach. While attempting to make a red lake pigment, he accidentally used potash contaminated with animal oil, resulting in the precipitation of an unprecedented deep blue. This was the first synthetic pigment in modern chemistry history.

The formula for Prussian Blue was initially kept strictly secret, limited to the Berlin court. After the recipe leaked in the mid-18th century, it quickly swept across Europe. It was dozens of times cheaper than Ultramarine and extremely strong in tinting power, making deep blue an affordable color for commoners for the first time.

Japanese Ukiyo-e underwent a visual revolution thanks to Prussian Blue. Dutch traders at Dejima in Nagasaki brought Prussian Blue pigment into Japan. The deep blue waves and Mount Fuji in Hokusai's 'The Great Wave off Kanagawa' were rendered possible precisely by imported Prussian Blue.

In the late 19th century, Prussian Blue was partially replaced in the West by Cobalt Blue and synthetic Ultramarine but broke new ground in architecture. The cyanotype blueprint process used Prussian Blue as a photosensitive agent; architects and engineers used it to copy drawings, which is where the term 'blueprint' originates.

Van Gogh used Prussian Blue extensively in the last two years of his life. He mixed Prussian Blue with Chrome Yellow to create the swirling, dizzying deep blue night sky in 'The Starry Night.' This bottomless blue, along with his spiritual world, continues to burn to this day.