Problems of fading of pink dyes: study on Carthamin and its degradation processes

Abstract

This thesis is the result of a collaboration with the Textile Research Department of the Royal Institute for Cultural Heritage of Brussels and the Victoria and Albert Museum of London. The project of the research deals with an actual problem: the fading and degradation processes that affect dyes employed in textile works. In particular, this study was focused on Carthamin, a pink red dye from Safflower petals detected, thanks to HPLC-DAD analysis, in some historical textile objects stored by the Victoria and Albert Museum. Specific ageing tests were performed on new silk samples dyed with Carthamin. Knowing that light represents the main and the deepest studied problem for Carhamin, it was chosen to investigate also the influence of some other parameters, like temperature, relative humidity and ozone. At prearranged intervals, HPCL-DAD analysis and spectrocolourimeter measurements were repeated on the aged samples in order to detect any change promoted by the ageing factors. The ultimate aim of the research is practical and actual: to provide information and suggestions helpful to conserve in a correct environment the objects dyed with Carthamin.