Blue is a color widely held to be most people’s favorite color. While some may find it cold, it’s psychological impact is generally thought to be serene, calming the mind and aiding concentration.
For the painter blue has always been quite costly. During the Renaissance true blue, sometimes called ultramarine blue, was five times more expensive than gold. Its color was derived from lapis lazuli, a rare, semiprecious gemstone mined almost exclusively in Afghanistan since the 6th century, and imported to Europe through Venice.
There were a few alternatives, such as smalt and azurite, but none was stable when suspended in oils, and none had strong tinting strength or covering power. For centuries, artists managed with these imperfect pigments using ultramarine as they, or their patrons, could afford. But when synthetic blues started to be made, a whole new world of potential opened up.
In about 1706, the German chemist and the color maker Heinrich Diesbach was sharing the Berlin laboratory of an alchemist, Johann Konrad Dippel. Dippel was preparing so-called “animal oil” – an alchemical concoction supposed to cure all ailments – by distilling blood and adding potash, while Diesbach was working on more practical projects for various private clients. Up against a deadline for one such client, Diesbach rushed to manufacture a batch of Florentine lake, a red pigment derived from boiled cochineal insects, alum, iron sulfate, and potash. Lacking this last ingredient, he borrowed some from Dippel, unaware that it had been contaminated with hexacyanoferrate from Dippel’s “animal oil” concoction. The next day, Diesbach returned to the lab to discover a deep blue precipitate, rather than the expected red material.
The two men quickly realized the commercial value of this new blue pigment. Dippel relocated to the Netherlands, where he began manufacturing his own Prussian Blue, while Diesbach remained in Berlin. Relying on word-of-mouth and sales through trusted contacts, Dippel and Diesbach realized high profits from the pigment, whose secret formula they guarded closely. In 1724, however, the English chemist John Woodward published a method for producing Prussian blue in the London Journal, ‘Philosophical Translation of the Royal Society’, opening up production in various European countries.
As revolutionary as Prussian blue proved to be, it was a mere precursor to the explosion of available colors brought about by the Industrial Revolution. Indeed, the French government played an active role in catalyzing innovation at the dawn of the 19th century, as the country emerged from the Revolution with its economy in disarray. The newly appointed administrator of the Sevres Porcelain Manufactory, Alexandre Brongniart (1770-1847) oversaw chemist Louis Jacques Thenard (1777-1857) as he developed the next synthetic blue, a vivid cobalt blue pigment, inspired by the traditional cobalt oxide blue glazes seen on 18th century Sevres porcelain. In late 1803-1804 he published his successful experiments roasting cobalt arsenate and cobalt phosphate with alumina in a furnace. By 1807, production in France had begun. The pigment was, and still is relatively expensive. Variant hues of cobalt blue followed Thenard’s discovery. He had unlocked the complexities of cobalt mineralogy, including cobalt violet, green, and yellow. Cerulean blue, a cobalt stannate, was introduced in the 1860’s. In spite of its limited tinting strength and hiding power, landscape painters soon favored cerulean blue for skies.
French Ultramarine Blue
The third major synthetic blue to emerge was the culmination of centuries of searching for a cheap, plentiful, high-quality replacement for the most valuable of all pigments: natural ultramarine. In 1824, the French government announced a competition among chemists to develop a true synthetic ultramarine. The prize was finally awarded in 1828 to Jean-Babtiste Guiment (1795-1871). Painters at last had an affordable, fully balanced palette of cool and warm colors spanning the full spectrum. This fact, combined with the innovation of ready-mixed oil colors in collapsible metal tubes, greatly facilitated the ability of painters to capture a range of observed natural effects en plein air (outdoors). Plein air painting culminated in Impressionism, which realized all the possibilities made available by the new spectrum of commercial paint colors. Like cobalt, the discovery of synthetic, or “French” ultramarine led to the development of variant hues, notable ultramarine violet, of the defining colors on the Impressionist palette.