Color Swatch created using heavy application/medium application/50% tint and was applied on acrylic primed canvas (7 oz) material.
This color contains the following pigments:
PR112—Naphthol Red AS-D
Pigment Type
organic, monoazo
Chemical Name
n/a
Chemical Formula
C24H16Cl3N3O2
Properties
This Naphthol Red is an intense scarlet red pigment that is heavily staining. It has an average drying time. It is semi-transparent and has relatively poor covering power.
Permanence
This Naphthol Red has been rated as having excellent lightfastness under ASTM testing, but other testing methods have demonstrated some tendancy for the color to fade with exposure to strong ultraviolet light. It has been considered a replacement for less lightfast naphthol reds such as PR3. Not suitable for exterior use.
Toxicity
Naphthol Reds are not considered toxic. Naphthol Red AS-D may cause eye, skin, or respiratory irritation. Contact with dry pigment should be avoided.
History
Unknown.
Alternate Names
Naphthal, Naphthol Bordeaux, Naphthol Carbamide, Naphthol Carmine, Permanent Carmine, Permanent Red, Fanchon Red.
PR188 —Naphthol Red
Pigment Type
organic monoazo
Chemical Name
n/a
Chemical Formula
C33H24Cl2N2O6
Properties
This Naphthol Red is yellowish, with a high tinting strength and average drying time. It produces warmer shades and tints.
Permanence
This Naphthol Red has excellent lightfastness, though it is generally not considered adequate for exterior use.
Toxicity
Naphthol Reds are not considered toxic. They may cause eye, skin, or respiratory irritation. Contact with dry pigment should be avoided.
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.
Alternate Names
Naphthal, Naphthol Bordeaux, Naphthol Carbamide, Naphthol Carmine, Permanent Carmine, Permanent Red.
PR108—Cadmium Red
Pigment Type
inorganic, cadmium
Chemical Name
cadmium sulfide and cadmium selenide
Chemical Formula
CdS × CdSe
Properties
Cadmium Red is a bright, warm red that ranges in shade from orange-red to maroon and is available in light, medium, and dark versions. It is strong and opaque, with good tinting strength. Cadmium Red dries slowly. It grays down when mixed with white, mixes well with blues to create a range of browns, and mixes well with Cadmium Yellow to create a strong orange. It also works well in neutral mixes. Cadmium pigments have been partially replaced by azo pigments, which are similar in lightfastness to the cadmium colors, cheaper, and non-toxic. Hues vary by brand.
Cadmium Red is usually available in either a pure grade or a cadmium-barium mix. The cadmium-barium mix has the same permanence as pure Cadmium Red, but it has a lower tinting strength.
Permanence
Cadmium Red is lightfast and permanent in most forms, but like many cadmium pigments, it will fade in fresco or mural painting. Its improved lightfastness has helped it to replace Vermilion on the artist’s palette.
Toxicity
Cadmium Red is a known human carcinogen. It is extremely toxic if inhaled and slightly toxic if ingested.
History
Cadmiums get their names from the Latin word cadmia meaning zinc ore calamine, and the Greek word kadmeia, meaning Cadmean earth, first found near Thebes, the city founded by the Phoenician prince Cadmus. Metallic cadmium was discovered in 1817 by Friedrich Strohmeyer, but Cadmium Red was not introduced until 1907 in Germany.
Alternate Names
Cadmium Scarlet, Selenium Red.
PR170—Naphthol Red
Pigment Type
organic, naphthol AS
Chemical Name
n/a
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.
Toxicity
Naphthol Reds are not considered toxic. They may cause eye, skin, or respiratory irritation. Contact with dry pigment should be avoided.
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.
Alternate Names
Naphthal, Naphthol Bordeaux, Naphthol Carbamide, Naphthol Carmine, Permanent Carmine, Naphthol Crimson, Permanent Red, Permanent Red F3RK (more opaque), Permanent Red F5RK (more transparent).
