nigrosin
/ˈnaɪɡrəsɪn/
noun
- A black or dark blue synthetic dye used in inks, coatings, and biological stains.
- Nigrosin is often added to black ink to make it more opaque.
- The laboratory used nigrosin to stain bacteria for microscopic examination.
- The artist preferred nigrosin-based paint for its deep, lasting color.