The dried pigment of indigo (indigotin) can be ground up and mixed with a medium to make ink or paint. Different concentrations of the dried pigment can create different hues of blue, from bright lapis lazuli to blue-gray, but the more the pigment is extended, the less light-fast it becomes. Similarly to textiles, there are no natural green colorants, so indigo was often mixed with vegetable yellow or orpiment (derived from arsenic). Indigo’s main use was for fresco and water-based paint and ink, though at times it was mixed with oil-based mediums as well.
Image: Maya Blue paint on an ancient Maya mural. (Image credit: Constantino Reyes/Azulmaya.com)
Maya Blue, as mentioned on the “Ancient World” page, was an indigo paint made by the Maya of Central America. They created this paint by mixing indigo with a white clay mineral, and used it for decorating pottery and temple frescoes. Similarly, in the Classical world, indigo imported from India was also used to paint frescoes, but many Classical artists had to be careful of counterfeit versions of indigo.
Image: Indigo Ink Tablet, Qing Dynasty (c. late 19th century), China. Held at the Metropolitan Museum of Art 30.76.207.
In the East, indigo was in widespread use as pigment for inks, especially because indigo is non-corrosive. It was often mixed to make other colors, commonly blue-green and sky blue. In China, indigo was the standard blue ink, and many Indian and Persian manuscripts often had borders of plain indigo blue with other hues of blue as detailing.
In addition to paints and ink, indigo was also used to dye paper, leather, and parchment. Ancient Egyptians would dye leather to make them into decorative hangings and canopies, and a decorated leather funeral canopy dyed indigo blue (dating to the 21st dynasty) was discovered. Blue was a favored color for religious texts; ecclesiastical codices from the Byzantine Empire had dyed bindings and pages, and similar practices were also utilized by Islamic scholars for their religious works. Religious scrolls from Japan were also dyed with indigo, a prime example of this being the Nigatsudō Burned Sutra, dating around 744 CE, held at the Metropolitan Museum of Art.
Image: Nigatsudō Burned Sutra, c. 744 CE, held at the Metropolitan Museum of Art in New York. It is a hanging scroll; silver ink on indigo-dyed paper.