title: Caput mortuum: spectroscopic and structural studies of an ancient pigment.
abstract: The use of a pigment variously described as caput mortuum, usta or ostrum to provide a deep purple colour in ancient wall-paintings was highly prized, despite the technical difficulties associated with its application. With the Raman spectroscopic characterization of pigments in ancient frescoes and wall-paintings becoming more widespread, it is timely to consider the identification of this material either as a generic haematite alone or in admixture with contemporary blue pigments. Here, Raman and infrared spectroscopic, X-ray diffractometric and scanning electron microscopic structural studies have been undertaken to characterize caput mortuum and to identify a specimen of Roman wall-painting dating from the 3rd century.
authors.affiliation: Department of Chemical and Forensic Sciences, University of Bradford, UK.
authors.forename: Luiz F C
authors.initials: LF
authors.lastname: de Oliveira
authors.forename: Howell G M
authors.initials: HG
authors.lastname: Edwards
authors.forename: Ray L
authors.initials: RL
authors.lastname: Frost
authors.forename: J Theo
authors.initials: JT
authors.lastname: Kloprogge
authors.forename: Paul S
authors.initials: PS
authors.lastname: Middleton