indigo

Ingredients

leaves of indigo-producing plants

Preparation Steps

Original Recipe Text

The leaves had to be fermented before they became a proper dyeing agent. The textile (or parchment) would then be dipped into a vat containing this substance and left to dry in the air to generate an oxidisation that would make the blue colour come out (p. 76). For parchment, a cold vat technique may have been used, involving soaking the parchment in water with a drop of detergent before dipping and stretching it afterwards to prevent shrinkage and cracking (p. 76).

Evidence

"The dye of the Blue Qur’an was, in all likelihood, based on a vegetal pigment: indigo."

Remarks

Recent microscope observation of its parchment at x45 magnification by Kristine Rose has revealed that the blue is not a crust of pigment but consists of extremely fine crystals of blue colour (p. 76). These crystals recall the insoluble form of blue that materialises when a dye solution oxidises on exposure to air, whereas a painted surface would have been particulate (p. 76). The parchment is deeply saturated with blue, showing a gradation where the hue becomes lighter deeper into the substrate, suggesting repeated dips into a vat (p. 76).