Prussian blue, discovered in 1704 or 1705, is generally regarded as the first of the modern colors. In truth it is something of an anomaly, appearing well before the blossoming of chemistry as a science in the late eighteenth century. Like so many other innovations in color, it was the result of a serendipitous accident.
Rublev Colours Aqueous Dispersions are pigments dispersed in water ready to be mixed with water-based mediums. These dispersions are especially made for use with traditional painting mediums, such as egg tempera, casein tempera, fresco, watercolors and distemper (glue tempera). They are also ideally suited for use with gesso to make toned grounds for drawing and painting. Pigment dispersions from Rublev Colours contain only naturally-derived ingredients, in addition to pigment and water, making them ideally suited for traditional mediums. Unlike other pigment dispersions that are typically made for acrylic medium, Rublev Colours Aqueous Dispersions do not contain coalescent solvents, artificial dispersing resins and other additives that interfere with natural mediums. Aqueous Dispersions make preparing traditional mediums easy; you do not have to hassle with powders, grinding pigments in medium and calculating binder ratios to make water-based paint. They make adding the right amount of paint binder, such as egg yolk, a no brainer because the right amount of water is already contained in the dispersion, simply add egg yolk.
Origin and History
|Current Names: ||English: Prussian blue|
French: bleu prussien, bleu de Prusse
German: Preussisch Blau
Italian: azzurro di Prussia
Japanese: konjō, berensu
Russian: берлинская лазаурь
Spanish: azul de Prussia
|Synonyms: ||English: Berlin blue, iron blue, Milori blue, Paris blue, Turnsbull blue|
German: Berlinerblau, Pariserblau, Turnbullsblau
Italian: azzurro di Berlin
Spanish: azul de Berlin
A Berlin-based color maker, Heinrich Diesbach, was working in the laboratory of the alchemist Johann Konrad Dippel, and in the course of preparing a red lake pigment, Diesbach asked Dippel for some potash (a potassium alkali).
Presumably to economize, Diesbach requested a batch of potash contaminated with oils prepared from animal blood. It was a false economy, for his pigment turned out very pale. Attempting to concentrate it, he succeeded instead in turning it deep blue. He had no idea what had transpired, but was astute enough to recognize the blue material as a potential pigment in its own right, and was soon manufacturing it according to a jealously guarded recipe.
Iron blue was first mentioned in 1710 in a Latin text written by an unknown author and its properties were described in a reference from 1726. It is said to have been discovered by the chemist and painter Diesbach in 1704, but other sources mention the chemist Johann Conrad Dippel, for whom Diesbach worked.
The first mention of its manufacture was by the English chemist John Woodward in 1726. Potash and ox blood were heated until they glowed and then subsequently boiled with rainwater. The "blood lye" obtained in this way was heated together with a sulfate and alum. This produced a green intermediate product, also called "mountain green" or "crysocollage green." The material was then washed and filtered. After a treatment with hydrochloric acid, the product eventually turned to a deep blue color. It was particularly valued for mixing light blues, and appears in skies by Watteau, Canaletto and Gainsborough.Source
Our Prussian blue is made according to the process originated by the French colormarker, Milori & Company, Lyons, France. Permanence and Compatibility
Prussian blue verditer is stable in weak acids, but is decomposed by weak alkalis, so it is suitable for oil, encaustic (non-emulsified type), egg tempera and watercolor, but not fresco and casein.Toxicity
Prussian blue is not considered toxic, however, care should be used in handling the dry powder pigment to avoid inhaling the dust.Rublev Aqueous Dispersion: Prussian Blue
|Colour Index: ||Pigment Blue 27 (77510:1)|
|Chemical Name: ||Iron(III) Hexacyanoferrate(II)|
|Chemical Formula: ||Fe4[Fe (CN)6]3|
|ASTM Lightfastness Rating|
|Specific Gravity: ||1.7|
|Refractive Index: ||1.56-1.662|
|Oil Absorption: ||45 g oil/100 g pigment|