Prussian blue
First modern synthetic pigment, used in art, medicine, and uniforms.
Prussian blue (also known as Berlin blue, Brandenburg blue, Parisian and Paris blue) is a dark blue pigment produced by oxidation of ferrous ferrocyanide salts. It was created in the early 18th century and is the first modern synthetic pigment. The pigment is used in paints, became prominent in 19th-century aizuri-e Japanese woodblock prints, and is the traditional 'blue' in technical blueprints. In medicine, orally administered Prussian blue is used as an antidote for certain kinds of heavy metal poisoning, and it is on the World Health Organization's List of Essential Medicines.
- chemical_formula
- Fe4[Fe(CN)6]3
- also_known_as
- Berlin blue, Brandenburg blue, Parisian blue, Paris blue
- synthesizer
- Johann Jacob Diesbach
- field
- Pigment, medicine, military uniform dye
- known_for
- First modern synthetic pigment; antidote for thallium and caesium poisoning; traditional blue in blueprints
Lore & Background
The pigment is believed to have been accidentally created when Diesbach used potash tainted with blood to create red cochineal dye. Instead, the blood, potash, and iron sulfate reacted to create iron ferrocyanide, which has a distinct blue hue.
Reader's Guide
Prussian blue is significant as the first stable and relatively lightfast blue pigment widely used since the loss of knowledge regarding the synthesis of Egyptian blue. European painters had previously used indigo dye, smalt, Tyrian purple, and the extremely expensive ultramarine from lapis lazuli. Japanese painters and woodblock print artists likewise lacked a long-lasting blue pigment until they began to import Prussian blue from Europe. In medicine, Prussian blue is used as an antidote for heavy metal poisoning, exploiting its ion-exchange properties and high affinity for certain 'soft' metal cations. It is on the World Health Organization's List of Essential Medicines. The pigment lent its name to prussic acid (hydrogen cyanide), derived from it. From the beginning of the 18th century, Prussian blue was the predominant uniform coat color of the Prussian Army, and continued to be worn by most German soldiers for ceremonial occasions until World War I. Despite being prepared from cyanide salts, Prussian blue is not toxic because the cyanide groups are tightly bound to iron.
Did You Know?
- Prussian blue is used as an antidote for thallium(I) and radioactive caesium poisoning and is on the WHO List of Essential Medicines.
- The pigment lent its name to prussic acid (hydrogen cyanide), called Blausäure ('blue acid') in German.
Frequently Asked Questions
What are Prussian blue's powers/role?
In the arts it serves as a paint pigment and was a signature color in 19th-century aizuri-e Japanese woodblock prints, while in medicine it functions as an oral antidote for thallium and caesium poisoning. It also traditionally supplies the blue ink for technical blueprints and has been used to dye military uniforms.
How does Prussian blue's story end?
Rather than having a narrative conclusion, Prussian blue remains in active, multi-field use to this day. Its medical role is locked in by its placement on the World Health Organization's List of Essential Medicines, guaranteeing continued availability for heavy-metal poisoning treatment.
Why is Prussian blue important?
It broke new ground as the first color deliberately created through chemical synthesis instead of being harvested from nature, launching the era of modern synthetic pigments. Beyond its artistic legacy, its ability to chelate toxic metals like thallium and caesium gives it a critical, life-saving role in emergency medicine.
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