blue dye

Ingredients

indigo, woad

Preparation Steps

Original Recipe Text

The parchment was dyed to a dark blue color (maṣbūgh samāʾī). Analysis of folios Arabes 389 and 390 at CNRS Orléans by Patricia Roger ruled out murex-derived purple due to the lack of bromine (p. 121, n. 107). Historical comparisons mention indigo or woad as likely candidates for such blue dyes in Mediterranean manuscripts (p. 120, n. 95).

Evidence

"The absorption curve of the diffuse reflection spectrum did not suggest the presence of purple; the alternative hypothesis of a mixture of colouring agents including murex purple was also ruled out by the absence of bromine (a constituent of natural purple) from the X-ray fluorescence spectra."

Remarks

The opacity of the blue dye on the parchment meant that a template grid could not be viewed by transparency, necessitating the drawing of actual ruling lines on the surface (p. 119, n. 88). There is scholarly debate regarding whether the color was intended to be 'blue' or 'hyacinth purple' based on ambiguous terminology in historical sources (p. 120, n. 92).