Prussian Blue

An accidental discovery

The story of Prussian blue is a very good example of how scientific discoveries often happen. In the early 18th century, a Berlin color maker named Diesbach was producing a very nice red in which he used potash, or potassium. One day, he happened to buy potash from a chemist named Dippel.

Dippel, an unscrupulous chemist, sold him adulterated potash. Using this substance to precipitate a cochineal decoction to which he added iron sulphate, Diesbach, to his great surprise, did not obtain the expected red but a superb deep blue. Not understanding what had happened, Diesbach turned to Dippel who immediately saw the fantastic business potential of this new blue. Dippel refined Diesbach's recipe and came up with a deep and solid blue that could be used on large surfaces, something that artists had not been able to find up to that time.

Until that time, pigments used in the making of blue where either rare and expensive or not very satisfactory. Hence, blue was not used very much by artists and dyers. The discovery of Prussian blue is said to have contributed to the popularity of blue in the European cultures of the 18th century, a popularity that remains very strong to this day.

Pastoureau, Michel ; Dictionnaire des couleurs de notre temps ; Paris, Christine Bonneton, 1999 ; 255 pages ; Collection Symbolique et société.
Delamare, François et Bernard Guineau ; Les matériaux de la couleur ; Paris, Éditions Gallimard, 1999 ; 160 pages ; Collection Découvertes Gallimard.