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Color Swatch

Pigment Info

00801-3742 — Primary Red

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:

PR48:3—Permanent Red
PR173—Rhodamine B Alumina Lake

PR48:3—Permanent Red

Pigment Type

organic, monoazo

Chemical Name

beta-oxynaphthoic acid lake, strontium salt

Chemical Formula

n/a

Properties

Permanent Red is a common name used for the strontium salt of beta-oxynaphthoic acid (BONA) lake pigment PR:48. It is substantially bluer than other shades of PR:48. BONA pigment lakes tend to have high tinting strength, however the tinting strength of PR48:3 is only average.

Permanence

Beta-oxynaphthoic acid (BONA) lake pigments are more lightfast than their beta-naphthol counterparts. Although their lightfastness makes them the pigment of choice in many applications, they may shift slightly in color or lose intensity under some conditions. Pigment PR48:3 has been reported to be the most lightfast of the BONA lake pigments.

Toxicity

n/a

History

Pigment Red PR48:3 is a lake pigment of beta-oxynaphtholic acid, a dye that resembles the common beta-Naphthol pigments. Beta-oxynaphthoic acid may have been synthesized as early as 1887. Commerical use of BONA lake pigments began in the 20th century. PR48:3 is used in printing, plastics, architectural paints, and industrial finishes.

Alternate Names

Brilliant Red

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PR173—Rhodamine B Alumina Lake

Pigment Type

organic, fluorone dye

Chemical Name

Rhodamine B Alumina Lake

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. The aluminum lake is reddish in tone.

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.