Hansa red
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Description
Originally a Hoechst AG trademark for a line of bright, transparent red synthetic organic pigments. Hansa reds, also called toluidine reds, are based on the reaction of beta-naphthol with 2-nitro-4-toluidine. Toluidine red was first synthesized in 1905. In general, toluidine reds have fair lightfastness and weather resistance, and they have a tendency to bleed. They are used in industrial coatings for air-dried and baked enamels and auto finishes. Toluidine reds are also used in wax crayons, pastels and watercolors.
See also Hansa.
Synonyms and Related Terms
toluidine red; Pigment Red 3; CI 12120
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Comparisons
| Pigment number (CI) | Pigment name | Manufacture | Comments |
|---|---|---|---|
| PR3 (12120) | Hansa Red3B, Toluidine dark red | unknown | often a dark, intense bluish red shade |
| PR4 (12085) | Hansa Red R-D, Chlorinated, para red, Toluidine red | unknown | yellowish-shade red |
| PR003 () | Studio red, helio | Kremer (#23950) | |
| PR004 () | Hansa red R (beta-naphthol) | unknown | sample from Tate Collection |
Risks
- Ingestion can cause cyanosis.
- Suspected carcinogen.
Physical and Chemical Properties
- Hue: ranges from yellowish-reds (like scarlet or fire engine red) to bluer reds (closer to crimson or ruby).
- Transparency: relatively transparent to semi-opaque
- Tinting strength: good to very good
- Lightfastness: early colorants had fair lightfastness, while more recent formulations have improved
- Stability: soluble in many organic solvents; resistant to acid, alkali and soap; not bleed resistant; very good heat resistance
Resources and Citations
- Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
- Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
- Monona Rossol, The Artist's Complete Health and Safety Guide, Allworth Press, New York, 1994
- B. Berrie, S.Q. Lomax, 'Azo Pigments: Their History, Synthesis, Properties and Use in Artists' Materials', Studies in the History of Art , National Gallery of Art, Washington DC, No. 57, 1997
- Clariant: Hansa Red B