Live Science has more on the Codex Purpureus Rossanensis, a 1,500-year-old, purple-paged book that seems to have been dyed with fermented, boiled urine:
For centuries scholars wondered how the precious purple parchments of the 1,500-year-old Byzantine book known as the Codex Purpureus Rossanensis were obtained.
It was generally assumed that Tyrian purple, extracted from Murex (sea snails) was used to dye the parchment sheets.
On the contrary, analysis have shown the mysterious purple resulted from the use of orcein, a natural dye extracted from the lichen Roccella tinctoria and processed with fermented urine, which at that time was the only source of ammonia.
“Even though early medieval illuminated manuscripts have been deeply studied from the historical standpoint, they have been rarely fully described in their material composition,” Marina Bicchieri, director of the Icrcpal’s chemistry lab, said.
Since X-ray fluorescence ruled out the presence of bromine, which is characteristic of Tyrian purple, Bicchieri turned to experimental data.
She prepared natural dyes using recipes described in the Stockholm papyrus, a manuscript written in Greek around 300 A.D. which contains 154 recipes for the manufacture of dyes and colors.
“Fibre optics reflectance spectra (FORS) showed a perfect match between the purple parchment of the codex and a dye obtained with orcein and an addition of sodium carbonate,” Bicchieri told Discovery News.
[via Archaeological News]