Great American Handmade Pastel - Dorian 4, 220.4

Pigment Information

This color contains the following pigments:

PW18-Calcium Carbonate

PBk28-Black Spinel

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

PBk28-Black Spinel

Pigment Type

inorganic

Chemical Name

copper chromite black

Chemical Formula

Properties

Black Spinel is a very neutral opaque black pigment, excellent for tinting to create neutral grays.

Permanence

Black Spinel has excellent lightfastness.

Toxicity

Black Spinel is mildly toxic. The pigment itself has an extremely fine particle size. It causes irritation and ulceration to skin. Respiratory exposure and exposure to dust are serious concerns.

History

Black Spinel is much more expensive than carbon-based blacks. Its use as a pigment has been limited to applications where a truly neutral black or gray tone is needed.