It was used in European easel painting since the Middle Ages. Marco Polo (13th century) was the first to report on the preparation of indigo in India.
Manufacturer / product code: Kremer / 36005 (V.1); Kremer / 36000 (V.2)
Chemical description: fermented extract from the leaves of indigofera tinctoria, precipitated with aluminium hydroxide. Kremer PDF
Color Index: NB1
More info: Pigments Through The Ages Colourlex
DOWNLOAD paper: “Pigments Checker version 3.0, a handy set for conservation scientists: A free online Raman spectra database”
DOWNLOAD paper: “FORS spectral database of historical pigments in different binders”