Prussian blue
A Berlin paint maker tried to make red, got blue, and changed art from Paris to Edo.
- Made from
- Iron salts and ferrocyanide
- First painting
- Van der Werff, Entombment of Christ, 1709
- Also
- An antidote for thallium and radioactive cesium
Around 1706 in Berlin, the color maker Johann Jacob Diesbach was making a red lake pigment from cochineal. According to a story published decades later, he borrowed potash tainted with animal blood from the alchemist Johann Konrad Dippel. Instead of red he got a deep blue, iron ferrocyanide: the first modern synthetic pigment. By 1709 it was being sold as Prussian blue, and a painting from that year, Pieter van der Werff's Entombment of Christ, is the oldest known to use it.
It was strong, stable and far cheaper than ultramarine, so it spread fast: Watteau was using it in Paris within a few years. Prussian infantry coats were dyed a dark blue of the same name. In 1782 the chemist Carl Wilhelm Scheele isolated a deadly gas from it, hydrogen cyanide, still called prussic acid; 'cyanide' itself comes from the Greek for dark blue.
Then it crossed the world. Japanese printmakers had no lasting bright blue until imported Prussian blue reached them, and Hokusai's The Great Wave off Kanagawa (1831), the first print in his Thirty-six Views of Mount Fuji, helped make it the color of a whole printmaking boom. In 1842 John Herschel's cyanotype process used light to form Prussian blue on paper, which is why architects' copies became 'blueprints'.
It has a second life in medicine. Swallowed, Prussian blue traps thallium and radioactive cesium in the gut, and it's on the World Health Organization's list of essential medicines. Its deep tone sits near navy and midnight blue, and mixed with white it gives the soft steel blues of the Great Wave's sky.
Swatches
- Prussian blue · mass tone (approx.)
- Prussian blue · tint with white (approx.)
Colors
Sources
- Kirby, J. & Saunders, D. (2004). Fading and colour change of Prussian blue. National Gallery Technical Bulletin 25.
- Bartoll, J. (2008). The early use of Prussian blue in paintings. 9th International Conference on NDT of Art, Jerusalem.
- World Health Organization, Model List of Essential Medicines (Prussian blue).
- Wikipedia, 'Prussian blue' and 'Cyanotype'.
Hex values are screen approximations. Every page lists its sources.