Old Holland Classic Artist Watercolor - Cobalt Violet Dark, 6 ml tube

Pigment Information

This color contains the following pigments:

PV23-Dioxazine Violet

PV19-Quinacridone Violet

PB73-Cobalt Blue Deep

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

PV19-Quinacridone Violet

Pigment Type

organic synthetic, quinacridone

Chemical Formula

C20H12N2O2

Properties

Quinacridone Red is a high performance, transparent pigment with an average drying time and uneven dispersal. It is another name for Quinacridone Violet (PV19) and Quinacridone Red (PR192). Quinacridone pigments have relatively low tinting strength in general. For this reason, quinacridone colors are often expensive, because more pigment is required in the formulation.

Permanence

Quinacridone Violet has excellent lightfastness and is considered the most lightfast organic pigment in this shade range.

Toxicity

Quinacridone Violet has no known acute hazards. Overexposure to quinacridone pigments may cause skin irritation. Quinicridone pigments contain a compound found to be a skin, eye, and respiratory irritant.

History

Although quinacridone compounds became known in the late 19th century, methods of manufacturing so as to make them practical for use as commercial pigments did not begin until the 1950s. Quinacridone pigments were first developed as coatings for the automotive industry, but were quickly adopted by artists.

Pigment Name

PB73-Cobalt Blue Deep

Pigment Type

inorganic

Chemical Name

cobalt silicate blue olivine

Chemical Formula

Co2SiO4

Properties

Cobalt silicate blue olivine is a transparent blue pigment with low tinting strength.

Permanence

Cobalt silicate blue olivine is permanent and lightfast. Its stability at high temperatures has made it a favorite in coloring glassware and ceramics.

Toxicity

Cobalt silicate blue olivine is mildly toxic and a respiratory irritant, but less toxic than some of the other cobalt salts used as pigments. In liquid form it is not considered hazardous.

History

Cobalt silicate blue olivine is a cobalt salt that is frequently used as a colorant in glass and ceramics. It has been used in natural mineral forms since ancient times. Techniques for manufacturing Cobalt Blue, a chemically pure salt of cobalt and aluminum oxide, were developed in 1802. Synthetic processes for other cobalt salts, including cobalt silicate blue olivine, were developed in the 19th century.