The chemical profile of Rubia tinctorum in wool dyeing and a novel fibre extraction method for compositional analysis

This report describes the understanding of natural dyes and the work necessary for analysis of historical textiles. Chapter 1 provides a general introduction into the background of historical dyeing, the methods used to extract these natural dye compounds used and how synthetic dyes overtook natural dyes in the commercial world of dyeing. Chapter 2 introduces and discusses the research undertaken with one particular natural dyeing plant, Rubia tinctorum (common madder). Dyeing studies were all performed on wool, and explore the dyeing properties of the madder plant. Dyeing studies with pre-mordanting and post-mordanting were undertaken. Chapter 3 explores the extraction of natural dyes from Rubia tinctorum and their identification. Extraction and analysis studies were conducted to obtain the ideal method for acquiring glycosidic anthraquinone dye molecules that could be used in the dyeing process. Chapter 4 focuses on identifying new methods to successfully remove glycosidic anthraquinone dye compounds from wool fibres dyed with Rubia tinctorum, whilst keeping their chemical structure intact. Further work in this chapter is undertaken to analyse glycosidic anthraquinone dye compounds successfully removed from photodegraded wool fibres and the comparison with current literature techniques used for historical sample analysis.