indigo carmine in·di·go carmine (ĭn'dĭ-gō')
Sodium indigotindisulfonate; a blue dye used for measurement of kidney function and as a stain for Negri bodies.
Turmeric, orchil, catechu, and indigo carmine are all extremely fugitive.
A less fast color is obtained with archil, indigo carmine and picric acid.
Bear in mind, that the indigo carmine dyes up slowly and requires a high temperature.
The preparation of indigo extract or indigo carmine from indigo is also a case of sulphonation.