An Experiment Gone Wrong!

Entombment of Christ by Peiter van der Werff

The above painting by Peiter van der Werff done in 1709, is the oldest known painting using the color, Prussian Blue. It is interesting that such a beautiful color was the result of an experiment gone awry. In fact, its maker, a fellow named Jacob Diesbach, was actually trying to make a red color, cochineal red lake, in his Berlin laboratory in 1706. A deep crimson can be obtained from female, cochineal, or scaly, insects. Diesbach needed iron sulfate and potash to complete making the pigment. In order to save money, he purchased some cheap, contaminated potash from an alchemist friend, potash contaminated with animal oil. When he mixed the contaminated potash with the iron sulfate and insect color, instead of a dark red, he got first a purple, then a dark blue pigment. It was the first synthetic blue pigment - Prussian Blue.

Blues were the colors most perplexing to artists up until Diesbach's experiment gone bad. Artists did not have a stable, plentiful blue to work with that was inexpensive. Ultramarine, which came from lapis lazuli and found in what is now Afghanistan was more expensive than gold. Indigo had a tendency to turn black with age and azurite turned green when used in frescoes.

So what happened chemically in Diesbach's experiment? The alkali, potash, reacted with the animal oil and formed potassium ferrocyanide. Mixing this with the iron sulfate, iron ferrocyanide was formed - Prussian Blue.

By 1750, because it was cheap to make, the pigment was widely used throughout Europe. In 1878, Winsor & Newton sold its own version of Prussian Blue. Notable artists who used the color were Gainsborough, Monet, Van Gogh, and Picasso. In the 19th century, the color was the base for dyes used in the making of German uniforms as well as inks. Pharmaceutical grade Prussian Blue has medicinal uses, being given to patients who have ingested thallium or radioactive cesium. And it is used by pathologists as a stain for iron in biopsy specimens.

All from an experiment gone wrong.

Just paint it!