On the Study of Historical Arraiolos Tapestries ; An integrated approach

Abstract

Abstract Wool sample collected from thirteen Arraiolos tapestries from the 17th – 19th century belonging to the National Museum of Ancient Art ( Lisboa, Portugal) collection were analysed to identify the natural dyes and mordants used in their making. Weld, indigo, spurge flax, brazilwood, madder and cochineal were identified in the fibres. Alum was the most commonly used mordant, but the presence of iron and zinc was also detected in some samples. Contemporary dyed fibres were used to evaluate the available methodologies for dye extraction from wool fibres . A procedure with Na2 EDTA in water /DMF (1.1, v/v) proved to be the most efficient for recovering the different choromophores. The Influence of mordant metal ion (aluminium, iron and cooper ) and dyeing technique on the fibre hue and photodegradation was studied in contemporary wool samples dyed with madder r brazillwood . Colour hue was strongly influenced by deying methodology and alum mordanted fibres showed the poorest lightfastness.