Michael Harding Artists Watercolor - Forest Green, 15 ml

Pigment Information

This color contains the following pigments:

PBr7-Raw Umber

PB15:1-Phthalo Blue

Pigment Name

PBr7-Raw Umber

Pigment Type

earth

Chemical Name

hydrated iron oxide

Chemical Formula

α-FeO3+(OH) or Fe2O3 × MnO2

Properties

Raw Umber is a cool, transparent brown ranging from yellowish brown to greenish brown. It has surprisingly good tinting strength, a high level of opacity, mixes well with greens, and is quick drying in oil form. It has excellent color properties and can create a variety of subtle, clear tints when mixed with white. It grays when mixed with blue and white. Raw Umber can tend towards chalkiness in dark mixes in oil form.

Permanence

Raw Umber has excellent permanence.

History

This pigment gets its name from the Latin word umbra, meaning shadow or shade. Its full name is listed as terra di ombra, meaning earth of shadow/shade, due to its original extraction from the area of Umbria, Italy. It has been used as a pigment since prehistoric times. Currently, the finest umber comes from Cyprus.

Pigment Name

PB15:1-Phthalo Blue

Pigment Type

organic

Chemical Name

alpha copper phthalocyanine

Chemical Formula

C32H16CuN8

Properties

Phthalo Blue PB15:1 is a structural variant of Phthalo Blue PB15 that produces more reddish tones.

Permanence

Phthalo Blues are completely lightfast and stable and are permanent for all paint uses. They are currently used in inks, coatings, and many plastics due to their stability and are considered a standard pigment in printing ink and the packaging industry.

History

Developed by chemists using the trade name Monastral Blue, the organic blue dyestuff now known as Phthalo Blue was presented as a pigment in November 1935 in London. Its discovery was accidental. The dark color was observed in a kettle where a dye was being made from a British dyestuff plant. The demand for such a pigment came from commercial printers who wanted a cyan to replace Prussian Blue.