Holbein Artists' Soft Pastel - Prussian Blue 2

Pigment Information

This color contains the following pigments:

PB27-Prussian Blue

PW6-Titanium White

Pigment Name

PB27-Prussian Blue

Pigment Type

inorganic

Chemical Name

ferric ferrocyanide/iron(III)-hexacyanoferrate(II)

Chemical Formula

Fe7(CN)18(H2O)x or C6FeN6H4N

Properties

Prussian Blue is a semi-transparent, deep cyan-blue with a greenish undertone and a very high tinting strength unequaled by most pigments. It is similar to Phthalo Blue unless mixed with white, when it gives up intensity and becomes smoky. It can behave erratically and less reliably in oil and watercolor form depending on its manufacture. For permanent painting Phthalo Blue is considered a more reliable choice.

Permanence

Prussian Blue is lightfast and permanent in all techniques except for fresco. When mixed with Zinc White in watercolor or tempera form, it fades upon exposure to light and completely regains its chromatic strength in the dark. Modern manufacturing techniques have made this tendency less of an issue in recent years

Toxicity

Prussian Blue is moderately toxic if ingested. It will emit toxic hydrogen cyanide gas if heated, exposed to ultraviolet radiation, or treated with acid.

History

"The first of the modern pigments," Prussian Blue is the first artificial pigment with a known history. It was discovered by accident in 1704 by the Berlin color maker Heinrich Diesbach, who was trying to create a pigment with a red hue by mixing iron sulfate and potash. The potash Diesbach purchased from a local laboratory had been contaminated by animal oil and blood during previous experimentation. The resulting mixture yielded a very pale red that changed to purple and then deep blue when he tried to concentrate it. Since previous blue pigments came from lapis lazuli, an expensive stone, Diesbach’s discovery was extremely important for artists of the time.

Pigment Name

PW6-Titanium White

Pigment Type

inorganic

Chemical Name

titanium dioxide

Chemical Formula

TiO2

Properties

Titanium White is the most brilliant of the white pigments. It is considered an all purpose oil color useful in all techniques and the best all around white. Its masstone is neither warm nor cool, placing it somewhere between Lead White and Zinc White. It is less prone to cracking and yellowing than Lead White, but it still yellows easily. Titanium White dries slowly in oil form, more slowly than Lead White but more quickly than Zinc White. It is opaque in oil and acrylic forms and semi-opaque in watercolor form. This pigment has good chemical stability, and its tinting strength is superior to both Lead White and Zinc White.

Permanence

Titanium White has excellent permanence and lightfastness.

Toxicity

Titanium dioxide is highly stable and is regarded as non-toxic.

History

Titanium is the ninth most abundant element in the Earth's crust, however mineral deposits that are economical to mine are less common. Titanium dioxide was first discovered in 1821, although it could not be mass produced until 1919. Widespread use of the pigment began in the 1940s. Since that time, it has become the most commonly used white pigment. The name comes from the Latin word Titan, the name for the elder brother of Kronos and ancestor of the Titans, and from the Greek word tito, meaning day or sun.