“The book on how one makes colours of all shades in order to illuminate books” Revisited

A new critical translation, revealing the science behind the documentary evidence and focused on establishing the chemical and technical rationale of the recipes in the Judaeo-Portuguese treatise on the art of illumination, the Libro de como si facem as côres, is presented. The rationale is based on laboratory reproductions of the treatises’ recipes for making pigments, colourants and binders, which are compared with those found in Portuguese medieval illuminations. The final products are fully characterized by XRD, Infrared, Raman and other relevant analytical techniques such as colourimetry. The processes for producing colourants and other materials important in paint are presented as worksheets. In order to illustrate the publication, photographs were taken of the reconstructions, with the most important sequences presented step-by-step. The details of the recipes that remain unclear are discussed. In this paper we will demonstrate our modus operandi for two colourants, vermilion and brasil lakes.