Nicker Painter’s Gouache - Carmine, 12 ml

Pigment Information

This color contains the following pigments:

PR17-Naphthol Red

PR170-Naphthol Red

BV10-Rhodamine B

Pigment Name

PR17-Naphthol Red

Chemical Formula

C25H20N4O4

Properties

Naphthol Red PR17 is only offered in watercolor form.

Permanence

This Naphthol Red has fair to poor permanence and always fade in tints. Not suitable for outdoor use.

History

Unknown.

Pigment Name

PR170-Naphthol Red

Pigment Type

organic, naphthol AS

Chemical Formula

C26H22N4O4

Properties

Pigment PR170 is a bright deep red with bluish undertones. It has an average drying time. It has two crystaline forms that differ significantly in opacity. The more transparent form (F5RK) tends to be more bluish and is less lightfast.

Permanence

The lightfastness and weatherfastness of Pigment PR170 varies, depending on the application and the crystaline form. The opaque form (F3RK) has very good lightfastness, and is more weather resistant. The transparent form (F5RK) has lightfastness that is considered acceptable in pure applications, but it fades more in tints. Neither form is considered suitable for exterior use.

History

Naphthol pigments are actually dyes that are "laked" to form pigments. First developed by the German chemical company Hoechst A.G. before World War I, their use in artist paints began in the 1920s. Pigment Red PR170 is a Naphthol AS pigment, chemically related to the diarylide yellow pigments. The Naphthol AS pigments comprise a range of reds. They are used in plastics, textiles, and printing inks.

Pigment Name

BV10-Rhodamine B

Pigment Type

organic, fluorone dye

Chemical Name

Rhodamine B

Chemical Formula

C28H31N2O3Cl

Properties

Rhodamine B is a staining violet dye that has fluorescent properties. It is extremely soluble in both water and alcohol. In art materials it is laked as a pigment.

Permanence

Rhodamine B, like all fluorescent dyes, is not considered to be lightfast. It is recommended for permanent works of art only if they can be adequately protected from exposure to ultraviolet light.

History

Rhodamine B, discovered in 1887, is used as a staining fluorescent dye in the biological sciences, for microscopy. It is also used as a laser dye. Because of its low cost, high tinting strength, solubility in water and alcohol, and relative stability for a fluorescent, it has sometimes been used as a food colorant, even though its use in food and cosmetics has been banned in most countries for many years. There have been several highly publicized recalls of food and cosmetic products contaminated with Rhodamine B.