Winsor & Newton Professional Watercolor - Davy's Gray, 14 ml Tube

Pigment Information

This color contains the following pigments:

PBk19-Slate Gray

PG17-Chromium Oxide Green

PBk6-Lamp Black

PW5-Lithopone

Pigment Name

PBk19-Slate Gray

Pigment Type

inorganic

Chemical Name

hydrated aluminum silicate

Properties

Slate Gray is a semi-opaque, neutral gray pigment produced from powdered slate.

Permanence

Slate Gray is absolutely lightfast.

Toxicity

Hydrated aluminum silicate is not considered toxic, however pigment from natural sources may contain impurities.

History

Mineral sources of Slate Gray have been used as a colorant since prehistoric times. 

Pigment Name

PG17-Chromium Oxide Green

Pigment Type

inorganic

Chemical Name

chromium oxide

Chemical Formula

Cr2O3

Properties

Chromium Oxide Green is a dull, dense, willow or pale green color that is completely opaque. It has an average drying time and a low tinting strength. It is fairly flexible in oil form and is suitable for all purposes and mediums. This pigment is less versatile in mixtures than Viridian and Phthalocyanine Green, but mixes well with other colors without overpowering them.

Permanence

Chromium Oxide Green has excellent permanence, even at high temperatures.

Toxicity

Chromium Oxide Green is slightly toxic. Evidence of Chromium(III) carcinogenicity is inconclusive. Chromium(III) salts appear in greenish pigments such as PG17. Chromium(VI) salts, which appear in yellowish pigments, have been proven to cause cancer.&nbsp

History

Louis-Nicolas Vauquelin discovered the element chromium in lead chromate in 1797. It began to be used as an enamel and ceramic color in 1809, but it had limited use as a pigment until 1862, because of its cost. It is the most commonly used green for military camouflage because it appears the same shade as living foliage under infrared light.

Pigment Name

PBk6-Lamp Black

Pigment Type

inorganic

Chemical Name

carbon

Chemical Formula

C

Properties

Lamp black is a very opaque, heavily staining black pigment that does not have much covering power. It is typically the most opaque black in watercolor form. Though a very pure black, it tends to muddy slightly in mixtures, is one of the slowest drying pigments in oils, and should not be used under other colors.

Permanence

Lamp Black is very lightfast and absolutely permanent. It is used in all techniques in permanent painting.

Toxicity

Lamp Black is slightly toxic by skin contact and inhalation. It is a possible human carcinogen.

History

Lamp Black is a carbon based black traditionally produced by collecting soot (known as lampblack) from oil lamps. It is the black found in Egyptian murals and tomb decorations and was the most popular black for frescoing until the development of Mars Black.

Pigment Name

PW5-Lithopone

Pigment Type

inorganic

Chemical Name

coprecipitated zinc sulphide and barium sulphate

Chemical Formula

Zn + BaSO4

Properties

Lithopone is a low tinting strength, semi-transparent white pigment that is often used as a filler or extender in other colors, or as the base for laked pigments.

Permanence

Lithopone is absolutely permanent and lightfast.

Toxicity

Lithopone is not toxic.

History

Lithopone was discovered by G.F. de Doubet in 1850. It  was developed commercially in the 1870s as a substitute or supplement for lead carbonate, to overcome the many shortcomings of white lead pigment, including toxicity, poor weathering, and darkening in the presence of sulfur compounds. It is used most often in interior paints and enamels. Its use as a white pigment has been superceeded in many applications by titanium dioxide.