Color Swatch created using Full Strength/50/50 and was applied on Cold Press Bristol Board (2-ply) material.
This color contains the following pigments:
PR49:1—Beta Naphthol Red
Pigment Type
organic, monoazo
Chemical Name
barium monoazo red lake
Chemical Formula
n/a
Properties
PR49:1, a barium salt of monoazo naphthol red, has a yellowish red tone.
Permanence
Pigments in the beta naphthol group are considered moderately lightfast. The naphthol AS pigments, which are more permanent, have largely taken their place in artist paints.
Toxicity
n/a
History
The Beta Naphthol colors were developed in the late 19th century. PR49 has been used in paints, plastics, printing inks, and cosmetics. Most of the PR49:1 pigment manufactured in the United States is used for printing and packaging applications.
Alternate Names
Barium Lithol Red
PV1—Rhodamine B
Pigment Type
organic, fluorone dye
Chemical Name
Rhodamine B
Chemical Formula
C28H31N2O3Cl
Properties
Rhodamine B is a staining violet dye that has flourescent 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.
Toxicity
The fluorescent dye Rhodamine B is toxic, and its use is banned in food, textiles, and cosmetics. It is harmful if swallowed, inhaled, or absorbed through the skin. It has been shown to be carcinogenic in rats when injected subcutaneously, producing local sarcomas. However, when it is laked as a pigment it can be biologically inactive and hence non-toxic. With proper preparation, the pigment Rhodamine B Lake is considered harmless, even if ingested.
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.
Alternate Names
Basic Violet 10, C.I. 45170, Rhodamine 610
