Benzimidazolone dyes
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Description
A group of disazo condensation dyes that contain the benzimidazolone functional group. Benzimidazolone colorants were first patented by Hoechst in the U.S. in 1960. Based on the fused aromatic benzimidazolone structure, in which nitrogen atoms stabilize the chromophore, they provide outstanding resistance to light, heat, and chemical agents. The series of yellow, brown, red, and violet dyes are very lightfast, have high chromatic purity, and excellent bleed resistance. Benzimidazalone dyes are used in printing inks, plastics, automotive coatings, wood stains as well as a few artists oil paints and watercolors.
Synonyms and Related Terms
2-benzimidazolinone; benzimidazolone (It.); naphthamide maroon [Daniel Smith]; carmine [Daniel Smith]
Dye Numbers and Characteristics
| Pigment number | Pigment name | Comments | Links to spectra |
|---|---|---|---|
| PY 151 | benzimidazolone yellow H4G | 1971; bright primary yellow; replacement for cadmium yellow | CHSOS spectra |
| PY 154 | benzimidazolone yellow H3G | 1960; warmer golden hue; semi-opaque | CHSOS spectra |
| PY 175 | benzimidazolone yellow | 1960; cool, greenish yellow; semi-transparent to transparent | |
| PR 171 | benzimidazolone maroon | 1965; an earthy brown-violet; semi-transparent | |
| PR 175 | benzimidazolone red HFT | 1965; intense mid-bluish-red | CHSOS spectra |
| PR 176 | benzimidazolone crimson | 1960; deep carmine red; transparent; used in toys and food-contact | CHSOS spectra |
| PO 36 | benzimidazolone orange | reddish orange; semi-transparent | |
| PO 62 | benzimidazolone orange | light red-orange; semi-opaque | |
| PBr 25 | benzimidazolone brown | 1960; dark, reddish-brown; transparent | CHSOS spectra |
Resources and Citations
- 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
- Website: www.handprint.com
- CHSOS: website
- Jackson Art Gallery: Jackson's Artist Pigments: Color Information and History; Jackson Art Colour
- Wikipedia: benzimidazolinone Accessed April 2026