
what do u see…
- aq group (double bonded O)
- no water soluble group (SO3- groups)
- no charge (neutral/nonionic)
history of vat dyes:
- indigo and tyrian purple are naturally occurring vat dyes
- indigo from plants, tyrian purple from shellfish
- synthetic indigo was first commercialized in 1897
- anthraquinone (AQ) based vat dyes were first commercialized in 1901
vat dye features

- colorants for cellulose or cotton
- water insoluble
- must be “vatted” for application
- converted to a water soluble (leuco) form by an alkaline reduction process
- high WF and LF (applies to AQ vat dyes)
- some causes catalytic fading or phototendering
- fixation mechanism= physical/mechanical entrapment