Describing the ‘elusive’ : Availability, Preparation and Use of Anthocyanin Colourants in Mediaeval European Illuminators’ Workshops

Anthocyanins are colorants which provide most of the blue, red and violet colours in numerous plants and fruits. Because of their great sensitivity to the slightest changes in pH and their instability in ordinary daylight, it is generally thought that these colorants were used only to dye everyday clothes in a domestic context. However, medieval artists’ recipe books not only describe these elusive substances, but also indicate their use in illumination. This is notably the case for the texts of the so-called ‘Strasbourg Tradition’, written in the south of Germany and the north of France between 1400 and 1560, and partly composed from an older Alsatian treatise on illumination. Departing from these sources, this paper details the methods employed to prepare these colorants and (re)evaluates their diverse uses in painting and illuminating techniques. This technical data subsequently served as a basis upon which to make reconstructions. Finally, an attempt to correlate the information provided by these recipe books with specific artistic practices was carried out by collating the descriptions with the results of analyses from contemporary illuminations by an Alsatian workshop active in the same geographical area.