Great American Handmade Pastel - Cyprus 4, 115.4

Pigment Information

This color contains the following pigments:

PV23-Dioxazine Violet

PW18-Calcium Carbonate

PBr7-Burnt Umber

Pigment Name

PV23-Dioxazine Violet

Pigment Type

organic

Chemical Name

carbazole dioxazine

Chemical Formula

C34H22Cl2N4O2

Properties

Dioxazine Violet is transparent and has very high tinting strength. It is a staining pigment, very dark valued when it is used at full strength. Concentrated, it paints out nearly black, but it mixes with Titanium White to form bright, opaque tints of purple. PV23 produces slightly redder shades than PV37. Because the hue can vary with the conditions of preparation and grinding, it may be offered in red shade, blue shade, and so forth.

Permanence

Dioxazine Violet has good lightfastness. There may be some concern about it fading or shifting in color in tints and washes. Some artists have reported that PV37, a molecular variant, is more lightfast than PV23.

History

Two molecular variants of Dioxazine Violet, PV23 and PV37, are available. They have similar properties, but mix slightly differently.

Pigment Name

PW18-Calcium Carbonate

Pigment Type

inorganic

Chemical Name

calcium carbonate

Chemical Formula

CaCO3

Properties

Calcium carbonate, the mineral constituent of chalk, is a low tinting strength, inexpensive white pigment that is often used is a buffer and filler. Because of its low tinting strength, it is overwhelmed by other colors. It is used in gesso and other coatings to give the surface more tooth, a desirable characteristic for some painting techniques.

Permanence

Calcium carbonate is lightfast. Like all carbonates, it reacts with strong acids

Toxicity

Calcium carbonate is completely non-toxic, and is used in many food, cosmetic, and pharmaceutical products. However, excessive consumption is not recommended. 

History

Naturally occuring chalk deposits have been mined since prehistoric times. Rocks and minerals that contain calcium carbonate include aragonite, calcite, vaterite, chalk, limestone. marble, and travertine. Calcium carbonate is the principle component of lime, used in many agricultural and industrial applications.

Pigment Name

PBr7-Burnt Umber

Pigment Type

earth

Chemical Name

iron oxides with manganese silicates or dioxide

Chemical Formula

Fe2O3,MnO2 or Fe2O3+MnO2+nH2O+Si+Al2O3

Properties

Burnt Umber is a more intense reddish brown pigment that results from heating the clay pigment Raw Umber. It has medium to excellent tinting strength and high opacity, and it is quick drying in oil form. Burnt Umber is somewhat more transparent than Raw Umber. It has excellent color properties and can create a variety of subtle, clear tints when mixed with white. It can tend towards chalkiness in dark mixes in oil form, but overall it mixes well with other colors. To create a black color in oil form, mix Burnt Umber with Phthalo Blue or Ultramarine. To achieve a similar color in watercolor form, mix it with Ultramarine or Payne's Gray.

Permanence

Burnt Umber has good permanence.

Toxicity

Burnt Umber itself is considered non-toxic. If contaminated by manganese compounds, it may be highly toxic if inhaled and moderately toxic if ingested.

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.